


The Adventure of the Two Students

by Gertrude_Granger



Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: Alternate Universe - Fusion, Friendship, Gen, Mystery, Post - Deathly Hallows
Language: English
Status: Completed
Published: 2012-05-01
Updated: 2013-02-10
Packaged: 2017-11-04 15:24:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 15
Words: 25,184
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/395336
Author URL: https://archiveofourown.org/users/Gertrude_Granger/pseuds/Gertrude_Granger
Summary: <blockquote class="userstuff">
              <p>Ten years after Harry Potter defeats Lord Voldemort, Hogwarts faces a new threat to its students. Luckily, first year Sherlock Holmes and his friend John Watson are on the case.</p>
            </blockquote>





	1. An Odd Encounter

**Summary for the Chapter:**

> Our heroes meet, and Professor Longbottom is a badass.

It was four against one. The boy was tall for his age, but he was all ivory skin and bones and ebony hair—no muscle to speak of—and it was painfully obvious that he had never thrown a punch in his life. He wasn't even trying to use his wand. _First year,_ John concluded.

"Not so cocky now, are you, smartarse?" one of the attackers shouted.

John didn't know who the boy was, or why the pack of Slytherins had targeted him, but he knew an unfair fight when he saw one. Walking away was not an option.

"Oy! Leave him alone!"

Four heads turned his way, their expressions ranging from surprised to worried to disdainful. The raven-haired boy slumped to the floor.

"What's it to you?" asked the one who seemed to be the ringleader. He was a big, burly kid, already a head taller than John, with a scar across his left cheek.

"Is he your _boyfriend?"_ asked another. His mates snickered. John rolled his eyes.

"Gay jokes—really mature," he said. "But then, I guess I shouldn't expect anything more from you lot. You think you're real tough, ganging up on that kid, don't you?"

"You offering to make things more even?"

Scarface took a step towards him, eyes bright and fists clenched. John pulled out his wand.

"I'm offering to let you off with a warning," he said. "Let him go."

"And if we don't?" asked Scarface.

He was clearly raring for a fight, but his cronies didn't look so confident. Maybe they recognized John from the last Quidditch match, when he'd batted a Bludger clear across the pitch, nailing the Slytherin Seeker right between the shoulders just as he was reaching for the Snitch. Or maybe they just realized that, as a third year, he would know more spells than all of them combined. The smallest of them, a weedy blond, put his hand on Scarface's shoulder.

"Seb," he whispered, "Seb, maybe we should—"

"Shut up, Nott," said Scarface, jerking his shoulder away. "If you're afraid, then I'll deal with him on my own."

"Oh, will you?" said someone right behind John.

Professor Longbottom was watching Scarface through narrowed eyes. John almost hadn't recognized his favorite teacher's voice, it was so uncharacteristically cold.

"That's bold of you, Moran," he said. "Especially considering Watson is older than you, possibly stronger, and definitely more experienced with dueling."

For one terrifying second, John thought the professor somehow knew about the incident with Angus Macnair the previous spring. Then he realized that, more likely, he was referring to the fact that John had studied jinxes in Defense Against the Dark Arts. The first years wouldn't be getting to that for months.

"But that's beside the point, really, since fighting is against school rules," Professor Longbottom continued.

"We were only joking around, Professor," said the weedy blond.

"Oh really?" said Longbottom. "And I suppose Mr. Holmes's nose started bleeding on its own?"

There was a pause. John rather enjoyed watching as each of the Slytherins tried very hard to think of a plausible explanation for the blood dripping down the raven-haired boy's chin.

"Detention for all of you, I think," said Longbottom. "Report to my office immediately after dinner tonight. And twenty points from Slytherin—each." He turned to John. "Mr. Watson, will you escort Mr. Holmes to the hospital wing?"

"Of course," said John.

The raven-haired boy was still sitting on the floor. John helped him to his feet and led him through the gang of Slytherins. None of them dared say anything, but Scarface gave them a look that nearly stopped John in his tracks. He had a sinking feeling that his new friend's troubles had just begun.

"Oh, and John?" Longbottom called. "Come and see me during your free period this afternoon. I'll be in Greenhouse Four."

"Yes, Professor," said John. He wondered if he was going to be praised or told off or both.

He knew he shouldn't feel disappointed about losing the chance to beat up a first year, but he did. It would have been so satisfying to give that berk what he deserved. Still, if a teacher had to come along at just that moment, Longbottom would have been his choice. The Herbology professor was notorious for his hatred of bullies; no one punished them more harshly.

John looked over at the cause of all this trouble. The boy had made no effort to clean up the blood on his face and robes, and his expression was oddly blank. John wondered if he was in shock.

"You all right?" he asked.

"Yes." The boy's tone was as emotionless as his expression. But then he met John's eyes, and there was a flicker of something, a carefully concealed emotion rising to the surface for a split second. "Yes, I'm fine. Thank you for helping me."

"Don't mention it," said John. "Holmes, is it?"

"Sherlock Holmes, yes."

The ridiculous names wizards gave their children never ceased to amaze John. Well, at least this one had a normal surname...hang on…

"You're not Mycroft Holmes's brother, are you?" he asked, frowning.

Sherlock glowered at him. "Much as I would like to deny it, yes."

Mycroft Holmes had been Head Boy the year before. John had only spoken with him two or three times, but those few encounters had been enough for him to develop an intense dislike. Mycroft wasn't as bad as some Slytherins—John had never heard of him beating up first years or calling people the M-word. But he was a pompous prat, sycophantic towards teachers and patronizing towards everyone else. John was glad the difference in their ages meant that he and Mycroft were only in school together for two years.

John studied Sherlock more closely. The boy was tall like Mycroft, and he had the same posh accent, but otherwise they couldn't have been more different. Judging by the look on his face, Sherlock didn't like his brother any more than John did. He decided not to hold the connection against him.

He sensed that Sherlock wanted to change the subject, so he said, "Slytherins don't usually go after their own kind like that."

"I'm not a Slytherin," Sherlock said. "I'm in Ravenclaw."

"Oh, sorry."

Sherlock shook his head in disgust. "Assuming that I'm in Slytherin just because my brother was! I don't assume you're in Gryffindor just because you bravely rushed to my defense a moment ago."

It was galling, being chastised by someone two years younger than him. John was so irritated that he nearly missed the compliment buried in Sherlock's words.

"Well, that's wise of you," he said. "Because I'm not in Gryffindor."

"No, of course not. Strong sense of justice, but little in the way of brains—you must be a Hufflepuff." Sherlock scanned John up and down. "And Muggle-born, too. No wonder you feel the need to overcompensate by excelling both in the classroom and on the Quidditch pitch."

John's mouth hung open. The kid talked like an adult, yet he didn't seem to have any grasp of basic etiquette. There was no malice in his voice as he declared John to have "little in the way of brains"—it was just an observation. To top it all off, the rest of his analysis was 100% accurate.

"How did you know—"

"Shouldn't we be going in there?" Sherlock asked.

John blinked. He had been so distracted that he had walked right past the hospital wing.

"Right," he said. "Er, just go in and tell Madam Pomfrey what happened. She'll have you patched up in no time."

"I should hope so, considering that's her job." Sherlock paused, his hand on the door, and looked back at John. "Thanks again."

"Er, no problem."

And with that, the boy was gone.


	2. An Upsetting Incident

**Summary for the Chapter:**

> Professor Longbottom continues to be awesome, and the plot emerges.

Professor Longbottom was showing his class how to prune a Bolivian Razor Bush without losing any appendages when John arrived at Greenhouse Four. The professor caught his eye and held up a gloved finger, the universal signal for, "Be with you in a moment." John nodded and took a seat in the corner.

The class was made up of Gryffindor fifth years; he knew because he recognized two of them from Quidditch. Sally Donovan was something of a Hogwarts celebrity, having scored the winning goal in a nail-biting match against Slytherin the year before. She was sitting with one of her teammates, a pasty bloke whose name John couldn't remember. Both had looked curiously at John when he entered the greenhouse. So had most of their classmates, but he was startled to realize that the pair were still watching him.

Smiling perfunctorily, he gave them a small wave. The bloke frowned and whispered something in Donovan's ear. She only continued to stare. Suddenly, John wasn't looking forward to the upcoming match against Gryffindor so much.

"Right, I'm going to let you all take a stab at it now," said Professor Longbottom. "Shout if you need me, and remember: safety first."

While his students put on their goggles and gloves and went to work, Longbottom walked over to John.

"How is Mr. Holmes?" he asked quietly.

"Fine, I think," said John.

"Do you know how it started?"

John shook his head. "Sherlock was already bleeding by the time I got there. I did hear one of them call him a smartarse, though."

Longbottom sighed.

"That's what I was afraid of," he said. "Sherlock Holmes is a true prodigy, and prodigies always have it rough, especially when they don't know better than to show off. You should have heard the things people used to say to Hermione Granger."

John could never get used to the way Longbottom would casually allude to his friendships with some of the most famous witches and wizards of the age. If anyone else reminded him that they were old school chums with Hermione Granger, John would think they were deliberately name-dropping. But Longbottom was too modest for that; John only knew the professor was a war hero in his own right because the other students talked about it.

"Actually, Hermione got bullied more for being Muggle-born," Longbottom continued. "At least Sherlock won't have to deal with that."

"That still happens," said John.

Longbottom looked at him curiously.

"I know, John," he said. "I just meant that the Holmeses are a very old wizarding family. No one who cares about that sort of thing is going to mistake Sherlock for a Muggle-born."

"Oh."

John felt his face flush. Of course that was what Longbottom had meant. Why did he have to go and blurt the first thing that came into his head?

It wasn't like John to let his mouth get ahead of his brain, but Longbottom had touched on a sore subject. Wizards and witches loved to talk about how terrible life used to be for Muggle-borns and how much better things were now that Voldemort was gone, as though the death of one person could eradicate prejudice overnight. They were kidding themselves. True, John had never been openly persecuted because of his heritage, but people treated him differently once they found out his dad was a butcher and his mum worked in a dress shop. They found a million subtle ways to remind him that he didn't fit in. Not all of it was malicious, but sometimes the well-meaning comments about how he could pass for pureblood were just as infuriating.

To his relief, Professor Longbottom changed the subject.

"John, we need to talk about how you handled the situation this morning. It was very noble of you to defend Sherlock, but threatening his attackers wasn't the answer. Next time, fetch a teacher."

John said that he would, but he had no intention of keeping his word, and he suspected Longbottom knew it. The professor had been thirteen himself once, and more recently than most of his colleagues. Surely he remembered that being labeled a snitch was far worse than getting detention for fighting. But if he felt compelled to play the responsible adult, then John would humor him.

"How did you get involved, anyway?" Longbottom asked.

John shrugged. "I just happened to pass by and see those Slytherins attacking him. It seemed like the only decent thing to do."

"You're not friends, then?"

"No. I'd never seen him before that moment."

"Oh." Longbottom looked disappointed. "Too bad. If anyone at this school could use a friend, it's Sherlock Holmes."

John was trying to think of an appropriate response when someone began shouting for the professor. He turned just in time to see Donovan's pasty companion fall to the ground.

Longbottom vaulted across the greenhouse faster than John would have thought possible for such a stout man. He followed instinctively.

"Anderson, how many times must I say to be careful?" Longbottom shouted.

John braced himself for an unpleasant sight. He wasn't particularly squeamish, but an accident with something called a Razor Bush had to be exceptionally nasty. He took a deep breath, looked down, and blinked in confusion.

There was not a drop of blood in sight. Anderson was writhing on the ground, his face twisted with pain, but he showed no signs of injury. Longbottom looked as bewildered as John felt.

"What happened?" he asked Donovan.

"I…I don't know," she stammered. "He just fell over. He seemed fine a minute ago."

Longbottom dropped to his knees.

"Anderson…Anderson, can you hear me?"

Anderson only groaned.

Longbottom examined the boy while the class watched helplessly. He checked his pulse, his breathing, his temperature. He even pried open his mouth and looked inside. Then the silence was broken by a gasp.

"His eyes!" shrieked a girl standing next to Donovan. "Look at his eyes!"

John leaned forward and gasped himself at what he saw. Anderson's eyes, which had been pale blue a moment ago, were now blood red.

For one second, Longbottom froze. Then he leaped to his feet.

"John, find the headmistress," he said. "Tell her a student has been…Tell her to meet us in the hospital wing."

John took off without so much as a nod.

As he sprinted up the hill, Longbottom's words replayed in his head over and over. The professor had stopped himself from saying something, and John thought he knew what it was.

_Tell her a student has been poisoned._


	3. A Disturbing Discovery

**Summary for the Chapter:**

> John worries. A lot.

John had never realized how quickly gossip spread around Hogwarts. Less than an hour after Anderson's mysterious fit, he went to Charms and found his classmates already speculating wildly.

"How'd you hear about it so fast?" he asked as he sat down between his two best friends, Mike Stamford and Henry Knight.

"I bumped into a couple of Gryffindors outside the loo," said Henry. "How do you know about it?"

"I was there."

He told them the whole story, including his suspicion of foul play. Both Mike and Henry were rather skeptical, until he mentioned the way Anderson's eyes had turned red.

"You mean they were bloodshot?" Mike asked.

"No, I mean his irises were solid red. It was the creepiest thing I've ever seen."

His friends looked at each other.

"What?" John asked.

He knew that look. It was the one Mike and Henry shared whenever their poor Muggle-born friend revealed his ignorance of something they considered common knowledge. That look was half the reason he studied so hard. He saw it less frequently the longer he lived in the wizarding world, but obviously, there were still some gaps in his knowledge.

"Red irises," said Henry. "The only thing I know of that causes that is Sanguinoculus."

"Sanguinoculus," John repeated. "I don't remember seeing that name in any of our set books."

"It wouldn't be," said Mike. "It's a Dark potion—extremely dangerous and extremely illegal. How the hell did Anderson get exposed to that?"

"I told you: someone must be out to get him," said John.

Henry murmured in agreement, but Mike still looked doubtful. "Why would anyone want to poison Anderson?"

"Well, he's a bit of a wanker," said Henry. "And he's on the Gryffindor Quidditch team, isn't he? Maybe someone in Slytherin or Ravenclaw is trying to take out the competition."

"Come off it," said Mike. "Who would attempt murder over Quidditch?"

John was about to reply that people had killed for stupider reasons when Professor Flitwick called the class to order. Not wanting to lose any points for Hufflepuff, he shut his mouth and put on his attentive student face. However, he found it difficult to concentrate on Soothing Spells with the image of Anderson writhing in pain fresh in his mind.

Making matters worse was the fact that he didn't know what had become of the boy. When they reached the hospital wing, Professor McGonagall had politely but firmly told John to go away. He had tried to peek in as she went through the door, but all he could see was a bit of blank wall. Was Anderson even still alive?

By dinnertime, everyone in the castle had heard about the incident in Greenhouse Four. Or rather, everyone had heard _something_. Depending on who you asked, Anderson was either lying comatose in the hospital wing, on his way to St. Mungo's in agony, or dead. The explanations for his state were even more varied: poison, dragon pox, an allergic reaction to Bolivian Razor Bushes. John suspected only the teachers knew the real story, and they were the only ones not talking.

He was beginning to lose hope of ever learning the truth when Mike plopped into the seat next to him, breathless and bursting with news.

"I stopped by Flitwick's office to ask him a question about the exam," he said, "and I overheard him talking with Hudson."

Professor Hudson was a motherly old witch who taught Potions. If anyone was likely to know about Anderson's condition, it was her.

"What did she say?" John asked, leaning forward.

"It was definitely Sanguinoculus," said Mike. "But Hudson doesn't keep that stuff lying around, and she doesn't teach students to make it, not even at the NEWT level. It's not a simple recipe, either."

"So it couldn't have been an accident," said John. "Someone must have made the potion in secret and slipped it into Anderson's pumpkin juice or something."

"Blimey, no wonder the teachers all look like someone has died," said Henry.

John glanced up and saw that Henry was right; the atmosphere at the teacher's table was unquestionably grim. Professor Hudson looked like she had been crying, and Professor Trelawney looked like she might start crying any minute. Flitwick's expression was calm enough, but when he went to cut his steak, John could see his tiny hands shaking from across the Hall. Longbottom and McGonagall were nowhere to be seen.

" _Has_ someone died?" he asked Mike.

"No," he replied. "Hudson said Madam Pomfrey got a bezoar in Anderson just in time. But they're all terrified. Apparently—" He broke off, glancing nervously at John.

"What?"

"Maybe I shouldn't say," he mumbled.

"Oh, come on!" said Henry. "You can't start to say something like that and then just stop."

"Fine," Mike sighed. "Apparently, Anderson is Muggle-born."

There was a pause.

"You think that's what this was about?" John asked, trying to keep his voice calm.

"That's what the teachers are afraid of," said Mike "Most of them were here when You-Know-Who was in power, you know, and during the whole Chamber of Secrets nightmare before that. Flitwick said that he was just beginning to believe those days were really over, and now this…But Hudson said he shouldn't jump to conclusions yet," he added hopefully.

John looked down at his plate. Suddenly, he felt no desire to finish his potatoes.

"I think I'm going to skip pudding," he mumbled, standing. "See you back at the dorm."

Neither Mike nor Henry tried to follow him, which was a relief. He felt bad enough without having to see the pity and concern in their eyes.

The common room was empty when he got there. He curled up in his favorite seat by the fire and pulled out _The Standard Book of Spells (Grade 3)_ , hoping to distract himself. However, he had no more success focusing on his homework than he had in Charms.

 _It might mean nothing,_ he told himself. Something like a quarter of the students at Hogwarts were Muggle-born. Anderson's lineage could very well be a coincidence.

And yet, it might not be a coincidence. Such things had happened before at Hogwarts. John would never forget the shock and horror he had felt when, as a first year, he learned about the Chamber of Secrets. Less than twenty years before, four Muggle-born students had been put in the hospital wing by a monstrous snake called a basilisk. Everyone had assured him that that could never happen again, that Harry Potter had destroyed both the basilisk and its master. But what if a current student decided that Tom Riddle had the right idea?

"Excuse me…John?"

John jumped. He had been so lost in thought that he hadn't noticed when other students began filtering into the common room; dinner must have ended. A small girl with brown pigtails was standing right in front of him. He vaguely remembered seeing her at the Sorting the month before, but he couldn't remember her name.

"Sherlock Holmes asked me to give you this," said the girl, holding out a folded piece of parchment.

"Er, thanks," he said, taking the note. He looked at her curiously. "Are you good friends with Sherlock, then?" he asked.

"Oh, no!" she said. "He just came up to me after Transfiguration and asked if I could pass this along. I was so surprised! We have Transfiguration with the Ravenclaws every week, but he's never spoken to me before today. But then, he doesn't speak to anyone much. He hardly ever opens his mouth, except to answer questions. But he does that a lot. He's an absolute genius. Are you friends with him?"

"Er, well…sort of."

"What's he like?" The girl leaned forward, getting a little too close for John's comfort. "Is he always so…mysterious?"

John honestly didn't know how to answer that question. He said as much, explaining that he had only met Sherlock earlier that day. Disappointed, the girl returned to her gaggle of first year friends.

What with the afternoon's excitement, John had nearly forgotten about his encounter with the strange boy. Now he opened the note eagerly, his curiosity was renewed.

_Meet me by the statue of Gregory the Smarmy at midnight._

_S.H._

He turned the note over, thinking there might be more written on the back. There wasn't. Apparently, Sherlock saw no need to justify asking John to break curfew for him.

John sighed. Well, he had a feeling he wouldn't have slept much tonight, anyway.


	4. A Midnight Meeting

**Summary for the Chapter:**

> Sherlock shows off his deductive skills and comes to a disturbing conclusion.

John had a secret: He loved wandering around Hogwarts at night. During the day, the corridors were crowded and chaotic, and there was always someplace he needed to be. He could never stop and really look at what had to be the most miraculous building in all of Great Britain. At night, he could explore the castle to his heart's content. The corridors were blissfully silent, and the constant danger of being caught only made it more exciting. These midnight strolls had become his favorite cure for insomnia.

But tonight there would be no solitary exploring. Tonight he was risking detention to meet with a boy he barely knew for reasons unknown. As he slipped out of the Hufflepuff common room, John wondered what he was getting himself into.

Sherlock was already waiting by the statue of Gregory the Smarmy when John got there. In the darkened hallway, he was nothing but a thin silouhette.

"You're late," he said, much too loudly.

"Shh!" John looked over his shoulder, half expecting to see Filch appear out of thin air, but the coast was still clear. He pulled Sherlock into the nearest classroom before their luck ran out.

" _Lumos_ ," he whispered. A tiny orb of light appeared on the tip of his wand, illuminating Sherlock's pale face. Madam Pomfrey had done her job well; John would never have guessed that hours ago the boy had been black and blue. His hair was still standing all on end, but maybe it always looked like that.

"Now, what's this about?" he asked Sherlock.

"I need to know more about the attack on that fifth year, and you're the only person I know who witnessed it," Sherlock answered promptly.

A dozen questions popped into John's head all at once. He decided to start with, "How did you know I was there?"

Sherlock gave him that look again, his "don't be an idiot" face. "I was right there when Professor Longbottom told you to meet him in Greenhouse Four during your free period. He only had one class in that greenhouse this afternoon."

"Oh. Right," John said sheepishly. "And, er, why do you need to know this?"

Sherlock sighed dramatically. "Just tell me what you saw."

Why John was taking orders from a first year, he couldn't have said, but the next thing he knew, he was telling the boy everything he could about the day's events. Sherlock listened intently.

"Bolivian Razor Bushes," he said when John finished. "So they were wearing protective gloves?"

"Yeah, and goggles."

"Goggles?" Sherlock furrowed his brow. "We aren't required to have goggles."

"No, Longbottom provided those."

Sherlock's eyes widened. Then, to John's surprise, he grinned.

"Yes!" he said. "Oh, yes! This is going to be even more fun than I thought! Come on!" Then he was out the door like a shot.

John managed to catch the door just before it slammed shut. Cursing, he hurried after the boy.

"Where are you going?" he whispered.

"Greenhouse Four, of course."

"Why?"

"To look for evidence, obviously!"

"Oh yes, _obviously_ ," John muttered. "Shouldn't you let someone more qualified do that? A teacher, maybe?"

Sherlock stopped and wheeled around so abruptly that John nearly walked right into him.

"Do you want to know how I knew you were Muggle-born?" he asked.

Bewildered, John nodded.

"You asked me if Mycroft was my brother. Anyone who grew up around wizards would already know that. We're from one of the oldest wizarding families in Britain, and our father occupies a prominent position in the Ministry of Magic. Plus, your shoes and book bag were clearly purchased in a Muggle shop."

John looked down at his trainers. No one had ever commented on them before, but now that he thought about it, he couldn't picture any of the shops in Diagon Alley selling Adidas.

"Okay, what about the other stuff you said?" he asked. "About me overcompensating and all that?"

"Longbottom knew that you had a free period during the time he would be in Greenhouse Four." Sherlock continued walking as he talked. "You must be quite the favorite for him to have your schedule memorized—you're not even in his house. And unlike some professors, Longbottom doesn't favor students based on bloodlines or anything as shallow as that, so you must be a good student. Additionally, your bag was all stretched out from being regularly filled with too many heavy books."

"And the Quidditch?" John asked, following him out of the castle.

"Your trainers were muddy, but the hem of your robe was clean. So you spend a lot of time outdoors, but not in your school uniform. From that, I deduced that you played Quidditch—Beater, most likely, given your build. The fact that my Slytherin friends seemed to recognize you and, with the exception of Moran, were intimidated by you, indicated that you've got quite a reputation there as well."

John shook his head in amazement. "Blimey, you're quick."

Sherlock smirked. "I know," he said. "Still think I'm not qualified for this?"

John didn't answer.

By this time, they had nearly reached their destination. It occurred to John that the greenhouses were probably locked at night. He opened his mouth to ask Sherlock if he'd thought of that, but then Greenhouse Four came into view, and he was distracted by a bigger problem.

Someone was already there.

John grabbed Sherlock by the back of his robes and dragged him behind the nearest tree. He started to protest, but John clapped a hand over his mouth. Then, cautiously, he peeked around the trunk.

Two figures stood in front of the greenhouse door. One was holding up a wand, its tip aglow. The other seemed to be trying to magic the door open. John couldn't see their faces, but he recognized the figure holding the light by her bushy hair.

 _"Alohomora!"_ said a gruff male voice.

There was a rattling sound; the intruder was pulling on the padlock.

_"Alohomora!"_

More rattling.

_"Alohomora!"_

"I told you it wouldn't work," said Donovan.

"I don't understand," said the male voice. "My uncle told me that when he was at Hogwarts, he used this spell to break into all kinds of places."

"Your uncle was at Hogwarts before the war. You know they've beefed up security since then."

"Why would they bother beefing up security on a bloody greenhouse?"

"Maybe for the exact reason we're all here," said Sherlock, stepping out from behind the tree.

The pair at the door wheeled around, wands raised. Donovan's light spilled over their faces, and John recognized her companion: Gregory Lestrade, the captain of the Gryffindor Quidditch team.

"What are you two doing here?" John asked.

"We could ask the same of you," said Lestrade. "Watson, right? And who the hell is this?"

"I know him," said Donovan, staring at Sherlock. "That's Mycroft Holmes's little brother."

Sherlock scowled. "I prefer to be called Sherlock, if you don't mind. And we're here for the same reason you no doubt are: We're investigating the attack on your teammate."

"Oh yeah?" Donovan looked skeptical. "Why? What does it matter to you?"

"It's a puzzle," said Sherlock. "I like puzzles."

"A puzzle?" Donovan looked outraged. "Someone nearly died!"

"Yes, yes, it's very unfortunate," Sherlock said impatiently. "But it happened, so I might as well take the opportunity to hone my powers of deduction. Now, if you'll excuse me…"

He moved towards the door, but Donovan blocked his way, arms crossed. Sherlock threw up his hands in exasperation.

"Look, we're on the same side here," he said. "Why should you care what my motives are, as long as I help bring your boyfriend's attacker to justice?"

At the word _boyfriend_ , Donovan turned bright red, and Lestrade burst out laughing.

"Oh, sorry," said Sherlock, looking from one to the other. "I didn't realize it was a secret."

"Come off it!" said Lestrade. "Sally and Anderson? She could do a damn sight better than him!"

He turned to Donovan, still grinning, as though expecting her to back him up. When Donovan only glowered at him, the grin slowly faded, replaced by an incredulous stare.

"No way," said Lestrade.

"Why not?" Donovan asked angrily.

"But…you're…and he's…Why didn't you tell me?" Lestrade looked hurt.

"Obviously, Donovan didn't want anyone to know she was dating a Muggle-born," said Sherlock. "Ridiculous, really. I spoke with Anderson once. His lineage is the least objectionable thing about him."

Donovan was spluttering with rage. In light of what Sherlock had just revealed, John couldn't find it in his heart to feel bad for her.

"Ashamed to be seen dating a Muggle-born, are you?" he asked.

"Of course not!" she snapped. "I wouldn't be with him in the first place if I gave a damn about that. It's just…my parents…"

While she was struggling to find the right words, Lestrade apparently decided he'd heard enough bickering for the night.

"Why don't we focus on the situation at hand?" he cut in. "We all want to find out what happened to Anderson, but we can't get into the greenhouse."

"You can't," said Sherlock. "I can. Step aside."

Without waiting for a response, he pushed past the two Gryffindors and dropped to his knees in front of the door. Then he pulled a small metal object out of his pocket and began prodding the padlock with it.

"Is that a lock pick?" John asked.

"A what?" asked Lestrade.

"A lock pick," Sherlock repeated. "A Muggle tool for picking locks. You really couldn't figure that one out for yourself?"

"What are you doing with a lock pick?" Donovan demanded.

 _"Picking a lock."_ Sherlock never looked up from his task, but John saw him grit his teeth in annoyance.

"Leave him alone," he said to Donovan. "A minute ago, you two were trying to break in using Alohomora. I don't see how using a Muggle lock pick is any more suspicious than that."

Donovan kept her mouth shut, but she still didn't look happy. John decided it would be best to ignore her.

"You never did tell me what you're hoping to find," he said to Sherlock.

"Sanguinoculus begins to take effect within minutes of exposure," said Sherlock, "which means that Anderson was poisoned in the greenhouse, right in front of you all. I presume he wasn't eating or drinking anything during class?"

He glanced over at Donovan, who shook her head.

"And if it were airborne, you all would have been affected," Sherlock continued. "That only leaves exposure through the skin."

Comprehension dawned on John. "It was on the inside of his gloves—or the rim of the goggles!"

Sherlock honored him with a rare grin. "Not so stupid after all!"

Lestrade looked at Donovan. "That would explain how Anderson survived," he said. "It would take affect more slowly through the skin."

"Okay, very clever," said Donovan. "So if you've already worked out how he was poisoned, then why are you trying to get in there?"

"To find out if the poison was on his gloves or his goggles, of course."

"Why does that matter?" she asked.

"Every student was wearing his or her own gloves, but Longbottom supplied the goggles," Sherlock explained. "If the poison was on the gloves, then someone must have sneaked into Anderson's room to put it on them. They targeted him specifically. But if the poison was on the goggles—"

"—then it was completely random," Lestrade finished. "Bloody hell, who would do that?"

"A psychopath," said Sherlock. He looked delighted at the thought.

At that exact moment, the padlock popped open with a soft _click._

"Finally!" said Sherlock, getting to his feet. He turned to the others. "Come along if you like, but stay out of my way and don't touch anything."

Donovan and Lestrade both expressed indignation at being bossed around by a first year, but John just silently followed him into the greenhouse. He was already getting used to Sherlock's outrageous ego. It was just as well, since Sherlock paid no attention to them whatsoever.

The greenhouse was quite creepy at night. The Bolivian Razor Bushes threw strange shadows on the walls, and the moonlight streaming in through the glass roof was tinged green.

"Where did it happen?" Sherlock asked. John led him to the spot where Anderson had fallen. His gloves and goggles lay forgotten on the floor.

"Perfect!" said Sherlock, grinning. "I was afraid they'd left them on until he got to the hospital wing. That would complicate things."

"So how do we test them for poison?" John asked.

"Oh, it's really quite simple." Sherlock reached into his pockets again. This time he pulled out a rag and a small glass bottle full of something pink.

The others watched in silence as he went to work; even Donovan seemed fascinated. First, Sherlock poured a little of the pink stuff onto the cloth. Then he carefully rubbed it onto the inside of the gloves and goggles. Finally, he spent several seconds staring intently at his handiwork. Just when John was starting to get bored, he held out the goggles. The potion smeared on the inner rim was now bright blue.

"The poison was on the goggles," Sherlock announced.

There was a long pause while they all thought about what that meant. John didn't know how to feel. On the one hand, it was a relief to know this wasn't a hate crime. On the other hand, someone out there was apparently poisoning things at random, which was even more terrifying.

"So what now?" Lestrade asked eagerly. Donovan shot him an exasperated look.

"Now we wait for him to strike again," said Sherlock.

 _"Again?"_ John asked, horrified.

"Of course." Sherlock began packing up his equipment. "This was a completely random act of violence. It was done for _fun_. Sooner or later, the culprit is going to want to have some more fun. Hopefully, next time he'll make a mistake, some little slip-up that'll lead us right to him."

"Are you suggesting we just sit back and wait for someone else to be poisoned?" Donovan asked. "What if they next time, someone dies?"

"Oh, I doubt that will happen," said Sherlock. "Everyone is on the alert now. People will start carrying bezoars in their book bags."

"But what if—"

"Well, this has been very productive," he continued. "Goodnight!"

Before anyone could say anything else, he began briskly walking back up the hill.

John shook his head. He started to follow Sherlock, but Donovan pulled him back.

"What are you playing at, hanging out with that little freak?" she asked.

John yanked his sleeve out of her grasp. "He's not a freak," he said coldly. "Just freakishly clever."

"Right, _just_ clever," Donovan sneered. "Did you see the look on his face when he said the poisoning was random? You'd have thought Christmas had come early!"

John opened his mouth to protest, but found he had no idea what to say. To be honest, he had been a bit creeped out by Sherlock's attitude himself. And why did he feel the need to defend this boy, anyway?

"He's just a kid, Sally," said Lestrade. "And it's none of your business who Watson hangs out with, anyway. Come on, let's go."

John decided that he liked Lestrade. He gave the Quidditch captain a friendly nod as he passed, though he avoided looking at Donovan.

John's last thought as he finally climbed into bed was that he had made a new friend. He wasn't entirely sure if that was good news.


	5. An Interesting Interview

John was miserable all the next day, partly due to lack of sleep, but mostly due to fear. There was no doubt in his mind that Sherlock's deductions were correct. There was a true psychopath at Hogwarts, and anyone could be his next victim. Throughout every class, John waited for someone to burst through the door and announce that the poisoner had struck again. It felt like his stomach was tied in a knot.

But the day passed without event. So did the next day, and the day after that. Anderson returned to class the following week. Slowly, people began talking about other things again: classes, Quidditch, the latest celebrity gossip. (Apparently, Harry and Ginny Potter were expecting another baby.) Life went on.

John saw Sherlock every so often in the corridors and the Great Hall. With no developments in the poisoning affair, they had little to talk about, but John made a point of always stopping to chat regardless. Sherlock didn't seem to have any other friends; he didn't even walk from one class to another with the other Ravenclaw first years. On the bright side, Moran and his gang seemed to be leaving him alone. John liked to think that was his doing.

By December, John had begun to relax. It looked like Sherlock had been wrong about the poisoner. Maybe whoever it was just really hated Anderson. Maybe they had no intention of harming anyone else.

Then, one sunny morning right before the Christmas holiday, John stepped out of the Hufflepuff common room and found himself face-to-face with Sally Donovan.

"Er, hello," he said.

"There's been another attack," she said without preamble.

Instantly, the knot in John's stomach returned.

"Who?"

"A Ravenclaw girl, Sarah Sawyer. You must know her—she's in your year."

John's heart sank. He did know Sarah, in the sense that he saw her every time the Ravenclaws and Hufflepuffs had class together. She was very pretty, but she was also very quiet, and he could never think of a good excuse to talk to her. Now he wished he'd tried harder.

"Is she okay?" he asked.

"I don't know," said Donovan. "The teachers aren't talking, but I think word would have gotten out by now if she were dead."

John told himself that Donovan was probably right. Then the tightness in his stomach worsened as he remembered something.

"Sarah is Muggle-born," he said.

"Yeah, so I hear," said Donovan. "One poisoned Muggle-born might have been an accident, but two in a row? That can't be a coincidence."

"But Sherlock said the attacks were random."

Donovan gave him an odd look.

"What?" he asked.

"Has it occurred to you that he might have been trying to throw us off track?"

It took a moment for John to realize what she was suggesting.

"Come off it," he said. "Are you saying that _Sherlock_ had something to do with this?"

"He seemed to know an awful lot about Sanguinoculus, didn't he? And he was able to get into the greenhouse."

"That doesn't prove anything."

"And he's pureblood."

"So are you!"

"I didn't _smile_ at the thought of a psychopath in Hogwarts."

John didn't have a response for that, so he just walked away.

"I'm warning you, Watson!" Donovan called after him. "Stay away from that kid!"

John didn't look back. He didn't want Donovan to see how much she had rattled him.

Deep down, he knew he wasn't being entirely reasonable. Donovan's theory made more sense than he wanted to admit, and if she really believed that Sherlock was dangerous, then telling John had been an act of kindness. Apparently, his loyalty to Sherlock outweighed his common sense.

_A true Hufflepuff, _he thought wryly.__

He couldn't have explained why he was so sure Sherlock was innocent. It was a gut feeling, with no basis in logic or facts. But gut feelings were usually correct…weren't they?

* * *

John wasn't surprised to find Sherlock waiting for him outside the Great Hall. However, he was a bit taken aback when the first words out of the other boy's mouth were, "I need you to go to the hospital wing."

"Why?" he asked warily.

"That girl was found in her dormitory," said Sherlock. "Apparently, someone sprinkled Sanguinoculus over her bedsheets."

John shuddered. "Okay, that's horrible, but I don't see what—"

"Think, John! Think! What does that location tell us?"

John thought about it.

"It means the poisoner targeted her specifically."

"There you go!" Sherlock bounced on the balls of his heels. "See? You're moderately clever when you try."

"Thanks," said John. If Sherlock picked up on the sarcasm, he chose to ignore it. "So you were wrong before, when you said the attacks were random."

Sherlock made a frustrated noise. "No! Anderson was poisoned randomly, but this girl was not. The culprit has changed his methods. The question is, why?"

John looked at him doubtfully. "But Anderson and Sarah are both Muggle-born."

"If they both had red hair, would you assume the poisoner was out to rid the world of gingers?"

"Er, probably not."

"Of course not. You would assume it was a coincidence. And there are more Muggle-borns than gingers at Hogwarts."

John wasn't sure he accepted that argument, but he could see that Sherlock wasn't going to back down. He decided it would be easiest to humor him for the time being.

"Okay, so you want me to go to the hospital wing and what, interview Sarah?"

"Yes. Find out if she's seen or heard anything suspicious lately. Maybe she was close to unmasking the poisoner."

"And you can't do this yourself because…?"

"I'm going to the scene of the crime."

"Of course." John frowned. "Hang on—if the poison was in Sarah's bed, then you can't go to the scene of the crime. Blokes can't get into the girls' dorms."

"How do you know that?" Sherlock asked.

John blushed. "Never you mind," he mumbled. It was a long story, and not one he was willing to tell in the middle of a crowded corridor. "Maybe Ravenclaw Tower is different, but if anyone male tries to go up to the girl's rooms in Hufflepuff, the stairs sort of melt into a giant slide."

As he explained the situation, John realized that this also meant the poisoner had to be female. Relief washed over him, followed by anger at himself. Why hadn't he thought of that when Donovan was accusing Sherlock?

Of course, Sherlock put two and two together much faster than he had. "Well, that's good news and bad news," he said. "On the one hand, we have half as many suspects now. On the other hand, I can't look for clues in person. I'll have to find someone female and not too stupid to go for me."

"Maybe you could ask Donovan," said John.

There was a slight pause. Then they both started giggling.

"Something funny?"

John turned. It was the girl with the pigtails who'd given him Sherlock's note the night after Anderson was poisoned. John had noticed her a few times since then, always near Sherlock, but never exactly with him. Sherlock must have noticed he'd gained a second shadow, but he never seemed to acknowledge her.

"Ah, Molly!" To John's surprise, Sherlock smiled at the girl. "Just the person I was looking for."

The girl turned a magnificent shade of red. "Am I?"

"Oh, yes," said Sherlock. "I suppose you've heard about what happened to that third year girl?"

"Of course." Molly's eyes widened. "You're still trying to find out who did it, aren't you?"

"Yes, and it turns out I can't do it alone."

"Hang on, Sherlock," said John. "This could be dangerous. Risking your own neck is one thing, but you can't ask Molly to risk hers for you."

His chivalry earned him a glare from Sherlock and surprisingly fierce protest from Molly.

"No, I want to help!" she said. "Both of my parents are Muggle-born. Sarah and that Gryffindor boy, they could be my distant cousins or something."

"That's highly improbable," said Sherlock. "Muggles aren't all interrelated the way wizards are."

"I don't think that's her point, Sherlock," said John. He sighed. "All right, tell her what to do."

"I need you to go to the scene of the crime and look for clues," said Sherlock.

"You mean Sarah's dormitory?" Molly frowned. "But I'm not in Ravenclaw. Won't I get into trouble?"

"Not if no one sees you. You have History of Magic next, right?"

"Right," said Molly. She blushed again, clearly thrilled to learn that Sherlock knew her schedule.

"The Ravenclaw third years will all be in Potions," said Sherlock. "That should give you plenty of time to make a thorough search. Unless you're dying to hear Professor Binns drone on about the Goblin Rebellion of 1299—"

"Oh, no! I'll do it!"

"Excellent!" Sherlock turned back to John. "I still need you to interview Sarah."

 _I must be as mad as he is,_ John thought as he headed for the hospital wing.

* * *

"Absolutely not."

"But Madam Pomfrey—"

"I said _no,_ Mr. Watson. Good day."

John caught the door before Madam Pomfrey could slam it in his face.

"Everyone is so worried about Sarah," he said in a rush. "The teachers haven't told us anything. You're going to have loads of people trying to see her. But give me five minutes with her, and I'll spread the word. I'll tell everyone that she's okay, but needs her rest, so they shouldn't disturb her."

Madam Pomfrey stared at him for a long moment. John could see that she was torn. On the one hand, John was obviously trying to manipulate her. On the other hand, the prospect of never having to argue with another one of Sarah's friends must have been tempting.

"Five minutes," she said at last. "And not a second more."

John breathed a sigh of relief. "Thank you."

"You're not to say anything that might upset her or get her excited."

"Of course not."

"Humph."

Sarah was sitting up in bed reading when Madam Pomfrey pushed back the curtain surrounding her. To John's surprise, she looked perfectly fine—until he got close enough to see her eyes. They were no longer blood red, but they were definitely tinged pink.

"You have a visitor, Miss Sawyer," said Madam Pomfrey. "If you don't feel up to it, I can send him away."

"Oh, please don't!" said Sarah. "I'm bored out of my mind."

Madam Pomfrey looked scandalized, as if the thought of anyone being bored in her infirmary was outrageous.

"Five minutes," she said again, before leaving in a huff.

Sarah looked at John expectantly. Even with pinkish eyes, she was quite pretty. He wondered if he should tell her so.

Instead, he said, "You look better than I expected," and instantly felt like a fool.

Amazingly, Sarah didn't seem offended. "I was only exposed to the Sanguinoculus for a minute," she said. "Almost as soon as I got into bed, I realized something was wrong and got up again."

"Well, that's fortunate."

"Yes."

Sarah was watching him curiously. Suddenly, he realized how odd this must seem to her. They had never even spoken before. Out of all the students at Hogwarts, why would he be the one visiting her?

"Er, listen," he said. "I have this friend who…well, he's trying to figure out who did this to you. You and Anderson, I mean. And he asked me to come and talk to you, to see if you know anything that might help us." Realizing how that must sound, he began backpedalling. "Not that that's the only reason I'm here. Obviously, I wanted to see if you were okay. But…er…"

"Tell Sherlock I'm very sorry, but I don't think I'll be much help," said Sarah.

John opened and closed his mouth several times.

"How did you know…?"

"He's in my house, remember?" She smiled at the look on John's face. "Usually he doesn't talk much, but after Anderson was attacked, he went around asking everyone about it. And everyone knows you two are friends, so…" She shrugged. "I'm no Sherlock, but even I could put two and two together there."

Beauty _and_ brains. More than ever, John wished he was talking to Sarah under different circumstances.

"So you have no idea who might have done it?" he asked.

Sarah shook her head.

"Believe me, if I had an inkling, I would tell you," she said. "I want this maniac stopped as much as anyone. But I don't have any enemies that I know of." She hesitated before adding, "Though I am Muggle-born. There are still people who don't like my kind around here."

"Our kind," said John. "Yeah, I know. But Sherlock is convinced this isn't about that. He thought maybe you knew something that someone didn't want to get out. Have you seen or heard anything suspicious lately?"

Sarah shook her head.

"Then I guess there's nothing else to talk about," he said, standing. "Sorry for bothering you."

"Oh, you can bother me anytime you like," she said.

Suddenly, Sarah's cheeks matched her eyes, and John was feeling much more cheerful. So, of course, Madam Pomfrey chose this moment to return and announce that John's time was up.

"See you when you're discharged, I guess," he said glumly.

"Bye," said Sarah. She looked as disappointed as he felt.

Madam Pomfrey insisted on leading John all the way to the front entrance of the hospital wing. She probably would have opened the door for him, too, but someone else beat her to it.

Into the room stepped two wizards John had never met before, but recognized immediately. He had seen their photographs nearly every day since entering the wizarding world, in _The Daily Prophet_ , in history books, and on Chocolate Frog cards.

Ron Weasley and Harry Potter.


	6. An Inconvenient Interlude

**Summary for the Chapter:**

> The Christmas holidays interrupt the investigation, but not for long.

John knew he was staring, but he couldn't help it. The most famous wizard of his generation was standing not three feet away. It was like meeting a Beatle.

"Mr. Potter! Mr. Weasley!" Madam Pomfrey seemed nearly as surprised to see them as John. "What are you doing here?"

"Morning, Madam Pomfrey," said Ron. "We're here to see the student who was p—"

"—brought in last night," Harry cut in. He was looking right at John. He tried not to look too much like a prat.

"Ah," said Ron, glancing at John. "Right."

Madam Pomfrey objected to anyone else seeing Sarah, though she did so in a much more polite tone of voice than she had used with John. Ron and Harry exchanged looks of mingled exasperation and amusement.

"Same old Madam Pomfrey," said Ron.

"We came all the way from London," said Harry. "At Professor McGonagall's request."

Madam Pomfrey pursed her lips.

"Watson!" she said abruptly, wheeling on John. "You've had your five minutes. Now run along!"

"Yes, miss," he said sullenly.

He gave Ron and Harry an awkward sort of half-bow as he backed out the door. Ron wasn't looking, but Harry nodded politely. John hurried away before he could embarrass himself any more.

Ten minutes later, he found Sherlock sitting alone at the Ravenclaw table. Breakfast was long over, but then again, John couldn't remember ever seeing Sherlock actually eat, anyway. He was engrossed in a book rather than food.

"You won't believe what just happened," he said, plopping into the seat next to him.

Sherlock looked up immediately.

"What? Did the Sawyer girl know something?"

"Oh. No, she couldn't tell me anything. But guess who turned up just as I was leaving?"

He told him the story in a rush. However, the presence of two of the most famous wizards in the world didn't seem to faze Sherlock.

"I was wondering how many students would have to be poisoned before McGonagall called the Aurors," he said. "Harry Potter and Ron Weasley are the obvious choice. They were solving mysteries at Hogwarts when they were our age."

Leave it to Sherlock to be irritatingly rational about everything. John would have to tell Henry and Mike about the incident later.

"So you didn't learn anything useful?" Sherlock asked.

"I guess not."

"Nor did Molly. I, however, had more success."

"Oh really? What have you been up to?"

Sherlock handed him a sheet of parchment. John could barely read any of it—Sherlock's penmanship was atrocious—but it seemed to be a list of potion ingredients.

"What's this?" he asked.

"A list of ingredients that were taken from the student supply closet in the last week," said Sherlock. "As well as a few that were stolen from Professor Hudson's private storeroom."

"Ingredients for making Sanguinoculus?" John asked eagerly.

"Oh no. Even Hudson's storeroom wouldn't have that. No, these are the ingredients for _the antidote_ to Sanguinoculus."

John mulled that over. "So someone was afraid they'd be poisoned next. That could have been anyone."

"Could it?" asked Sherlock, one eyebrow raised.

John sighed. "Could you skip the gloating and just get to the part where you tell me what's going on?"

"Look at the amount of each ingredient that was taken." Sherlock took the list back. "Four cups of beetle's eyes, three cups of belladonna, eight cups of powdered unicorn horn…it's enough to make gallons of antidote. One person would never need more than a mouthful."

"So they're making antidote for all of their friends as well?"

"Perhaps," said Sherlock, in a tone that said _Not likely._ "Or perhaps they're planning on selling it."

"They'll make a fortune, then," said John. "Every Muggle-born I know is convinced they're going to be poisoned next." His eyes widened. "You don't think…?"

"That the poisoner herself is trying to make a profit off of the hysteria she's created?" Sherlock nodded. "I think it's a definite possibility. Not certain, of course, but the best lead we've got so far."

John couldn't decide which was more despicable: poisoning people because of bigotry, or to make a few Galleons. Either way, he had never wanted to catch this psycho more.

"Let's take this to Ron and Harry right now," he said, standing. "They're probably still in the hospital wing."

"Ron and Harry?" Sherlock raised an eyebrow. "You're on a first-name basis with The Boy Who Lived and his best mate?"

"Well, what else am I supposed to call them? Potter and Weasley?"

Sherlock shrugged and went back to reading.

"Well, are we going to show them the list?" John asked after a moment.

"I don't see the point," said Sherlock. "They won't find anything."

"What?"

"By lunchtime, everyone in the castle will have heard that the great Harry Potter is here, including the poisoner. She won't attempt anything while they're here, and she'll hide or destroy anything incriminating."

"So what do you suggest we do?"

"We wait." Sherlock stood. "With Aurors here, the poisoner probably won't strike again until after the holidays. All we can do in the meantime is find out who took the antidote ingredients."

John followed him out of the Great Hall.

"Okay," said John. "Again, shouldn't we let Ron and Harry do that?"

"Why?" asked Sherlock. "I'm perfectly capable of obtaining that information by myself. I don't see any reason to bother them."

He abruptly came to a halt.

"Ah, there she is!" said Sherlock. He turned to John. "Wait here a minute."

John watched as the boy approached a painting down the hall. In it, two middle-aged women were chatting merrily. Sherlock went right up to the women and greeted them with a most un-Sherlock-ish warmth. John couldn't hear what they were saying, but the woman on the left seemed to recognize his friend. A few minutes later, Sherlock returned, looking satisfied.

"What was that all about?" John asked.

"Paintings, John," said Sherlock. "They can enter nearly any room in the castle. They're everywhere, see everything, yet most of the time people aren't even aware of them. If anyone is likely to know who took those ingredients, it's a painting. And Violet over there—" He nodded toward the lady he'd been speaking to. "—is the biggest gossip in the whole castle. I give it a week before she wheedles the information out of someone."

"How did you talk her into helping?"

"Oh, Vi and I are old friends," Sherlock said smugly. "I made a point of getting on her good side, just in case."

John could only shake his head. Sometimes he couldn't blame Donovan for being a little frightened of Sherlock.

"You'll be going home for the holidays, I suppose?" Sherlock asked when they reached the entrance to the Hufflepuff common room.

"Yeah. You?"

"Unfortunately."

He looked so glum that John considered inviting him to visit him in Aldershot, but he decided against it. He wasn't sure his parents could handle having two wizards in the house, especially when one of them was Sherlock Holmes.

So instead, he said, "Well…I guess I'll see you in January, then."

"I suppose so," said Sherlock. "Happy Christmas."

The younger boy made an odd, jerking movement that might have been the start of a handshake or a hug, but ended up being neither. Then he was gone without another word.

* * *

John had a spectacularly uneventful Christmas holiday. At first, he was grateful for the chance to relax, but by the second week, he was going stir-crazy. One could only lose so many games of Cluedo before wanting to throw the thing in a bin.

To keep from totally falling out of the loop with the rest of the wizarding world, he had arranged for _The Daily Prophet_ to be sent to him while he was at home. Although he skimmed the headlines every morning, he never saw a word about poisoned students or Harry Potter and Ron Weasley investigating a case at Hogwarts. Someone had gone to great lengths to keep that story from spreading any further than it already had.

"It's damage control," Mike said when he called John on Christmas Eve. (He was visiting his one Muggle grandparent, who had shown him how to dial a telephone.) "They don't want the whole community in a panic."

Every day, John wondered if Sherlock's plan was working. While he tried to figure out if Miss Scarlet used the candlestick in the ballroom or the kitchen, was the painted lady tracking down a real would-be murderer? Then he found himself wondering what Sherlock was doing. Was he as bored with his family of wizards as John was with his family of Muggles?

Upon finding himself back at Hogwarts on the second of January, John put his trunk back in his dorm and then immediately set out to find Sherlock. Once again, the boy was reading by himself in the Great Hall. When John went up to say hello, he wordlessly handed him a folded slip of parchment.

"What's this?" he asked.

"A late Christmas present from Violet," said Sherlock, grinning.

Realizing what he must be holding, John wasted no time in examining it.

Written on the parchment was a single name.

_Irene Adler._


	7. A Perfect Plan

**Summary for the Chapter:**

> John and Sherlock decide to catch Irene themselves. What could go wrong?

"She doesn't look like a criminal mastermind," said John.

He and Sherlock were sitting on a bench outside the castle. Anyone passing by would just see two friends enjoying the sunny winter day, but the spot gave them an excellent view of the group of Slytherins ice-skating on the Great Lake.

Sherlock raised an eyebrow at him. "What do you imagine a criminal mastermind to look like?"

"I don't know," said John, shrugging. "I just didn't expect her to be so…so…"

"Pretty?" Sherlock smirked. "Glamorous? Charming? Oh John, I thought you were smarter than that."

"That's not what I meant!" John said, but his flushing cheeks betrayed him.

The truth was, Irene Adler was _very_ pretty. Tall and slender, with green eyes and pale skin that contrasted sharply with her dark hair, she was the kind of girl John's mother always described as "striking." He couldn't help thinking about some of the rumors he'd heard that afternoon.

Irene had turned out to be very popular. Within an hour of getting her name from Violet, they had learned that she was in Slytherin, in her sixth year, and quite notorious for her romantic exploits. John thought most of the stories had to be exaggerated, if not completely made up. (How could you do _that_ on the back of a hippogriff?) However, judging by the number of boys vying for her attention, Irene wasn't doing anything to dispel the gossip.

Sherlock looked from Irene to John with mingled exasperation and amusement. "I thought you fancied that Sawyer girl," he said.

"So what if I do?" John asked, turning even redder. "I can fancy Sarah and still notice that other girls look nice."

Sherlock snorted. _"Hormones,"_ he said contemptuously. "I hope I never experience them."

John laughed. It was hard to imagine Sherlock experiencing anything as mundane as physical attraction. He amused himself for a moment by trying to picture it: Sherlock blushing and stammering as he asked some girl if she would like to join him in dusting for fingerprints.

Meanwhile, the real Sherlock was staring at Irene Adler in a very different way from the Sherlock in John's imagination.

"She must have a hiding place," he said abruptly. "Somewhere to stash her ingredients and mix the potions undetected."

"I heard there was a room somewhere in the castle designed just for hiding things," John offered.

Sherlock dismissed this suggestion with a wave of his hand. "Everyone knows about the Room of Requirement nowadays, thanks to Harry Potter. She'll have found someplace less flashy—an unused classroom, maybe."

"In a castle this size, there must be a million places like that. How are we going to narrow it down?"

"Give me a moment."

Sherlock suddenly became very quiet and very still. It looked like he was completely zoned out, but John knew better by now. The less Sherlock moved his body, the faster the gears were turning inside his head.

John put on his metaphorical thinking cap as well. It would be so satisfying if, just once, he solved the puzzle before Sherlock.

"Why don't you ask Violet to have all of the paintings keep an eye on Irene?" he asked. "Wherever her hiding place is, she'll have to go back to it at some point, right?"

"Violet is…less inclined to help me now," Sherlock mumbled.

"What did you do?"

"Nothing!" said Sherlock. When John continued to look at him accusingly, he amended this to, "I may have made some observations about her artist's shortcomings that she didn't appreciate."

John groaned. For someone so brilliant, Sherlock was incredibly stupid sometimes. It was a good thing John had better social skills, or they would really be in trouble.

"What about Lestrade?" he asked.

Sherlock looked up at him, startled. "What about him?"

"He's in the same year as Irene, so they probably have at least one class together. He can watch her more easily than us, and he has a personal stake in this."

Sherlock didn't respond.

"Come on. He's a good bloke." John had chatted with the Gryffindor Quidditch captain a few times since that night in Greenhouse Four, and he had always been pleasant.

"Given his choice in friends, I have to question his judgment," said Sherlock.

 _People have said the same of me,_ John thought. But all he said was, "Fine. Have it your way."

They sat in silence for a while. When Sherlock finally spoke, John actually jumped.

"Got it!"

Sherlock sprang to his feet and began heading back towards the castle.

"Got what?" John asked, following him.

"It's obvious, isn't it?" Sherlock didn't wait for an answer. "We'll never find the hiding place on our own, so we need her to lead us to it."

"But there's no telling when she'll need to go back to the place, and we can't watch her twenty-four-seven," said John.

"Obviously," Sherlock said again. "The only solution is to give her a reason to go there within a certain timeframe."

"Okay. How are you going to do that?"

Sherlock smiled in a way that made John very nervous.

"I'm not going to, John," he said. "You are."

* * *

The plan was really quite simple. The hardest part was getting Irene alone long enough to pull it off. John saw her around the castle all the time, but always amidst a flock of admirers. Finally, after two days, he decided to just ask her for a word in private. A perfect opportunity wasn't going to just present itself. Besides, he was beginning to feel like a creeper.

After getting the okay from Sherlock, he made his move. Irene was coming down the corridor, chatting merrily with a pretty blonde who was her most frequent companion. A gaggle of hopeful-looking boys trailed in their wake. John took a deep breath and stepped forward.

"Er, excuse me…Irene?"

She surveyed John from head to foot before saying, "Yes?"

"Could I have a word?"

Irene exchanged looks with the blonde.

"All right," she said.

They moved closer to the corridor wall, where they weren't obstructing the flow of traffic quite so much. The blonde and the gaggle of boys moved on, the latter looking deeply disappointed.

"Well, Mr. Watson, what's this about?" Irene asked. Her pale green eyes bored into John. He had never felt so self-conscious in his life.

"You know who I am?" he asked, then immediately felt like an idiot.

"Of course. How could I forget the Beater who ruined my house's chances of winning the Quidditch Cup this year?"

There was something about the way Irene said this, with a smile on her face, that was simultaneously charming and terrifying. John felt his face flush.

"I wouldn't say your chances were ruined," he said. "Theoretically, if Slytherin wins every other match…"

 _Get on with it,_ said a voice in his head that sounded suspiciously like Sherlock.

"Er, anyway…I heard you might be able to help me with a…a sort of problem I'm having."

Irene raised an eyebrow. "Is that so?"

"Yes. You see…I'm Muggle-born, and, er…"

"Worried about being poisoned?"

Apparently, Irene wasn't one for beating around the bush. John decided to follow her lead.

"Yes," he said. "Is it true you've got an antidote?"

"It might be." Now she was being coy. John had no idea what to make of this girl.

"Well, er, what would it take to get a _definitely?"_ he asked.

"Five galleons."

"Five galleons?" John quickly converted the sum in his head. "Isn't that a little steep?"

Irene shrugged. "I suppose that depends on how much you value your life."

"Right. Well, I don't have that much on me right now. Could I meet you somewhere and, er, make the exchange?"

"Of course. Meet me outside the Great Hall after dinner tonight."

Right on cue, Sherlock marched by, knocking into Irene as he passed.

"Oh, sorry," he said, barely glancing back at her.

"No problem," she replied, but Sherlock had already disappeared into the crowd.

Irene looked back at John. He tried to appear innocent.

"Must've been in a hurry to get to class," he said.

They said their goodbyes, and Irene hurried off to class. Watching her retreating back, John thought, _That was almost too easy._

* * *

The transaction itself was rather anticlimactic. John met Irene at the time and place she specified and handed over five Galleons. After pocketing the money, she handed him a vial filled with a honey-colored potion. Then she left with a wink. That was it.

But, of course, the transaction wasn't really the point.

Irene had barely disappeared around the corner before Sherlock came up behind John.

"Did it work?" John asked.

"Like clockwork," said Sherlock. "Come on, let's find someplace more private."

Moments later, in an empty classroom, Sherlock spread a piece of parchment out on the teacher's desk. John let out a low whistle.

On the parchment was a rough but accurate map of Hogwarts. It reminded John of the map Harry Potter was said to possess, but it didn't have little dots representing the castle's inhabitants. In fact, it had no markings at all, except for a single red line. As John watched, the end of the line moved down a corridor.

"Is that—?"

"Miss Adler, yes." Sherlock was looking incredibly pleased with himself.

John shook his head in amazement. He seemed to be doing that a lot since Sherlock had come into his life.

"So what did you find out?" he asked.

"See for yourself."

John traced the red line with his fingertip. It began right at the spot where Sherlock had dropped the tracking device into Irene's bag. From there, it went from one classroom to another, then down to the Slytherin common room, then to another classroom, then to the Great Hall.

"She went to class like normal," said John. "Charms, then History of Magic. Then she stopped by her dormitory before dinner, and—hang on, which classroom is that?" He pointed to the room Irene had visited right before the Great Hall.

"It isn't being used for any classes this term," said Sherlock, smiling. "I checked."

John grinned himself. "So that's it. We've got her."

"Not quite," said Sherlock. "We need to visit the hiding place in person. If she really is the poisoner, we'll find ingredients for Sanguinoculus along with the antidote. If she isn't…well, then we're back to square one."

"Well, what are we waiting for?" John asked, standing.

It was a rhetorical question, but Sherlock answered it anyway. "Nightfall," he said. "If we go now, someone might see us, which could complicate things."

John was anxious to see this case closed, but he couldn't deny that Sherlock had a point. And so it was that, once again, he found himself creeping around Hogwarts in the middle of the night. Professor Longbottom had hoped that John would be a good influence on Sherlock, but the exact opposite seemed to be happening; Sherlock was proving to be a bad influence on John.

They met at the statue of Gregory the Smarmy and walked to the unused classroom together. It was a longer walk than it had looked like on the map, and Sherlock's slippers seemed to make a ridiculous amount of noise. John grew more nervous with every step. However, they reached their destination without running into anyone. And that was where their luck finally ran out.

The light was on in the classroom.

"Damn it," Sherlock whispered. "Not this again!"

"Do you think it's Lestrade and Donovan?" John whispered back.

"I highly doubt they would get this far," Sherlock scoffed. "More likely, Adler returned to make another batch of antidote—or poison."

"Should we go in and confront her?"

"And reveal that we're onto her? She'll destroy the evidence before we can alert the authorities."

"But we'd be able to tell them what we saw."

"It will be our word against hers—assuming that she doesn't murder us both on the spot."

They were still debating what to do when the door flew open.

John pulled out his wand, ready for a fight. But the figure in the doorway wasn't Irene. It wasn't Lestrade and Donovan, either. It was Ron Weasley and Harry Potter.

For about five seconds, they all just stared at each other in confusion.

"You're not Irene Adler," said Ron.

"Very astute," said Sherlock, rolling his eyes. "Good to know the Ministry put their best men on this case."

"Shut up!" John whispered. They were about to be in enough trouble without Sherlock's sarcasm.

"Oh no, by all means, continue being a smartarse," said Ron. "That will really improve your situation. What are you two doing out of bed at this hour?"

"The same thing as you," said Sherlock. "Looking for evidence."

"I know you," said Harry. John was startled to realize that the man was looking at him and not Sherlock. "You were in the hospital wing the day we talked with Sarah."

"Yes, sir," said John. Beside him, Sherlock snorted.

Harry's expression softened. "You were visiting her as well?" he asked.

John nodded.

Harry turned to Ron. "A couple of kids sneaking around Hogwarts at night, trying to catch the person who hurt their friend," he said. "Sound familiar?"

"Just a bit," said Ron, his expression mirroring his friend's.

John felt a twinge of guilt. He did care about Sarah, but given that he'd never spoken to her before she was poisoned, he wasn't sure he really had a right to call himself her friend. Sherlock only saw her as another piece in the puzzle. It seemed wrong, somehow, letting Harry and Ron think this was some sort of act of devotion. But he couldn't think how to correct them without seeming churlish, so he said nothing.

Ron turned his attention to Sherlock. "And you are?" he asked.

"Sherlock Holmes."

"Sefton Holmes's son?"

"Yes, sir." Sherlock looked only marginally less annoyed at being identified this way than he had at being called Mycroft's brother.

"How did you two end up here?" Harry asked. "Have you been following us?"

John spoke before Sherlock could insult the Aurors' intelligence further. "No, sir. It's kind of a long story…"

He explained how they had found out about Irene from the paintings and tracked her to this spot. It took quite a while, because Sherlock kept butting in with clarifications and corrections.

"You made your own Tracking Map?" Ron asked Sherlock, amazed.

"Of course."

"But that's really advanced magic," said Harry. "Way beyond what they teach you in first year."

Sherlock agreed with him. "It's a good thing I've never depended on others for my education," he added.

"Bloody hell, Harry!" said Ron. "It's like someone used a Meshing Charm on you and Hermione. He even looks a little like you!"

"Yeah, and I suspect he's constantly going to be getting into trouble like me, too," said Harry. He didn't sound angry. In fact, John thought he saw a glimmer of admiration in the famous wizard's eye.

"Are you going to tell Professor McGonagall about this, sir?" he asked.

Ron and Harry exchanged glances.

"We probably ought to," said Harry.

"Seems a bit hypocritical though, doesn't it?" said Ron.

"Maybe we can let it slide just this once, if they promise not to do it again," Harry mused.

"We'll promise no such thing," said Sherlock.

"But you found the evidence, didn't you?" John asked, hoping to prevent a fight. "So it doesn't matter now, anyway. We've got her."

Ron and Harry sighed in unison.

"I'm afraid not," said Harry. "Here, you might as well have a look."

He led them into the classroom. The teacher's desk had been pushed to the side, revealing a hole in the floor where it had been.

"We cast every spell in the book, looking for hiding places," said Harry. "This was all we found."

John and Sherlock peered into the hole. Underneath was an empty space about two feet deep, and scrawled across the bottom in glittering red paint were two words:

_Nice try._


	8. A Terrible Turn of Events

**Summary for the Chapter:**

> His last brilliant plan was a failure, but Sherlock isn't giving up yet.

“She must have found the tracking device,” said John.

“Impossible,” said Sherlock. “It was disguised as an ordinary quill. Even if she noticed that it wasn’t one of hers, she wouldn’t guess its true nature.”

“She might have done, if she noticed you dropping it into her bag,” Ron said sharply. “Maybe you’re not as stealthy as you think.”

Sherlock bristled at the implication that he was capable of making a mistake. “How do you know this is our fault?” he demanded. “How did you two track her here, anyway?”

“With this,” said Harry, unfurling a sheet of parchment.

“The Marauder’s Map!”

John leaped to his feet, their setback forgotten for the moment as he examined the legendary map. It made Sherlock’s look like—well, like something an eleven-year-old had drawn. Instead of just tracking one person, the Marauder’s Map tracked _everything_ : every step of every living thing in Hogwarts. (And a few nonliving things—he noticed the Bloody Baron skulking around the dungeons.) John amused himself for a while by making the minuscule dot labeled “John Watson” move back and forth.

“Very impressive,” said Sherlock, though he didn’t sound impressed.

“Dead useful, that map,” said Ron. “It sees everything and everyone automatically. No need to go around dropping things in people’s bags.” He gave Sherlock a pointed look.

“Let it go, Ron,” said Harry. “When we were his age, we spent the whole school year following the wrong man.”

Ron mumbled something about bats and easy mistakes.

The mention of following people brought John back to the matter at hand. “What do we do now?” he asked.

“Well, without any hard evidence, we can’t accuse Miss Adler of anything,” said Harry. “But Ron and I can request an interview. Maybe she’ll let something slip.”

“Unlikely,” said Sherlock.

Harry sighed, frustrated. “I know, but what else can we do?”

“Search her rooms,” Sherlock said immediately.

“What good will that do?” Ron asked.

Sherlock gave the second most famous wizard alive his trademark “don’t be an idiot” look. For John, it was refreshing to see the look directed at someone other than himself for once.

“Where else would she hide the evidence?” Sherlock asked. “She had to move quickly, and I doubt she had a backup hiding place already lined up. She’s clever, but not _that_ clever.”

“What makes you think she’s still got the stuff at all?” Ron fired back. “She probably destroyed everything the moment she realized someone was onto her.”

Sherlock shook his head. “She’s invested too much in this endeavor to give it up so easily. She’ll have saved the potions if at all possible.”

“She’s too cautious for that,” Ron insisted.

Sherlock pointed to the glittering, red script. “Is that what you call cautious? Practically daring us to catch her?”

“All right, enough,” Harry cut in. “Boys, we appreciate you trying to help, but leave this to me and Ron. We’ll take Irene in for questioning in the morning—right after breakfast. Understood?”

John braced himself for another round of arguing. Then, to his amazement, it didn’t happen.

“Understood, sir,” Sherlock said calmly. “Thank you.”

He turned and left without another word. Baffled, John followed him.

“You’re giving up?” he asked, catching up to the younger boy.

“Of course not,” said Sherlock. “You heard what Potter said.”

“Er, yeah, I did. Hence my confusion.”

“Right after breakfast, John!” Sherlock bounced on the balls of his feet. “Why do you think he told us the exact time they’ll be questioning Adler?”

John sighed wearily. “I don’t know. Why?”

Sherlock grinned.

“So that we’ll know when her room is unguarded.”

* * *

Once again, Sherlock had Molly do his dirty work for him. John might have felt bad about letting him use the girl, had she not seemed so thrilled about it. She hung on Sherlock’s every word as he explained the situation to her over breakfast the next morning.

John wasn’t the least bit surprised to discover that Sherlock already knew where the entrance to the Slytherin common room was. However, he was a bit startled when Molly said she could get the password herself.

“I have this friend,” she said. “He’s not like other Slytherins. He doesn’t mind that I’m not pureblood at all. In fact, he’s as disgusted with the poisonings as anyone. He’ll be glad to help.”

“Oh.” Sherlock looked mildly impressed. “Well, that’s a bit of luck. Good thinking, Molly.”

At this tepid praise, Molly smiled as brightly as if Sherlock had declared his undying love.

Fifteen minutes later, the trio met in front of a blank stretch of wall in the dungeons. Molly said, “Mackled Malaclaw!” and a hidden doorway slid open before them.

John was suddenly struck by how much life at Hogwarts had warped his perception of normality. Three years ago, a door that was invisible until you said the right word would have left him slack-jawed. Now it wasn’t even all that impressive, let alone surprising.

“Do you remember the spell I taught you?” Sherlock asked Molly. “The one for revealing hidden compartments?”

Molly nodded.

“Good. Be thorough,” said Sherlock.

“But don’t take too long,” John added. “We wouldn’t want you to get caught.”

“You won’t get caught,” Sherlock countered. “We’ll be out here, keeping a lookout, the whole time.”

This was news to John. “We will?”

“Of course. What else would we do while she’s in there?” Sherlock looked genuinely puzzled.

“I was planning on going to class,” said John.

Sherlock made an exasperated sound. “Dull!”

“It’s not dull. I’ve got Defense Against the Dark Arts this period.”

“Dull!”

John tried to explain that not everyone had every set book memorized before they boarded the Hogwarts Express, and besides, there were consequences for skipping too many classes, but it was like trying to explain the concept of personal space to a cat. In the end, he left Sherlock standing guard outside the Slytherin common room.

It took about ten minutes for John to regret this decision. His body had moved to the Defense Against the Dark Arts classroom, but his mind was still down in the dungeons with Sherlock and Molly. Focusing on anything else was impossible.

_We’d better solve this case soon, or my marks are going to suffer,_ he thought.

The moment class was over, he bolted. He was so intent on beating the crowd back to the Slytherin common room that he almost didn’t notice Harry, Ron, and Irene emerging from an unused classroom.

John skidded to a halt and looked over his shoulder. Irene didn’t seem at all perturbed by her interrogation. In fact, she was looking a bit smug. Ron and Harry, on the other hand, were visibly frustrated. John didn’t bother turning back to ask how the interview had gone.

Moments later, he spotted Sherlock hurrying out of the Charms classroom, his fellow Ravenclaw first years straggling behind.

“I thought you were going to stay and keep watch,” said John.

Sherlock scowled. “McGonagall came by not long after you left,” he said. “She walked me all the way here, like a bloody child.”

“The nerve of her,” John said drily. “Well, come on. Let’s see if Molly had any luck.”

John realized something was wrong as soon as the descended the stairs to the dungeon; no doubt Sherlock noticed it sooner. The crowd should have been thinner on this level, where fewer students had reason to go, but instead it was even thicker. Worse, there was a tension in the air that was becoming all too familiar. Now on the alert, John began listening to the scraps of conversations going on around him.

“Did you hear?”

“Another attack!”

“Right in our common room!”

“Oh no,” John groaned.

He broke into a run, Sherlock right on his heels.

The throng was concentrated in and around the entrance to the Slytherin common room. If anyone noticed that the two boys pushing through the crowd weren’t in Slytherin, they were too preoccupied to say anything. It was just as well, since nothing was going to stop John from confirming with his eyes what he already knew in his gut.

Molly lay motionless on the common room floor.

Even through all of his horror and guilt, John couldn’t help thinking about what this meant for the case. Maybe Sherlock was rubbing off on him more than he realized.

“Irene couldn’t have done this,” said John. “Harry and Ron only let her go a few minutes ago. I saw them.”

Sherlock wasn’t listening. Wordlessly, he knelt on the floor beside Molly, his eyes roving up and down her small frame like a laser beam.

“What’re you looking for?” a Slytherin boy asked indignantly. John shushed him.

Gently, Sherlock raised Molly’s forearm. A golden wristwatch glinted as it caught the light.

“She wasn’t wearing that when she went into the common room,” he said.

“So what does that mean?” John asked.

Sherlock was already on his feet.

“It means the attacker has left us a message.”


	9. A Friendly Competition

**Summary for the Chapter:**

> John and Sherlock have different ideas about how to go about investigating the latest attack.

Professor McGonagall made a special announcement at dinner that evening.

“By now, you have all heard about the attack on Molly Hooper.” The headmistress, always a very serious woman, had never looked so grim. “I will be frank. Miss Hooper is alive, but her condition is very serious—far more serious than that of the two students who were poisoned last term. It appears that, rather than being exposed to a small amount of Sanguinoculus through her skin, as the others were, she was forced to actually swallow some.”

John felt like he might be sick. He looked around the Great Hall, wondering which of his classmates was capable of such evil. If the monster was present, then she was a remarkable actress; the faces surrounding him all looked as disgusted and terrified as he felt.

“I tell you this, not to frighten you, but to impress upon you the severity of the situation,” McGonagall continued. “These attacks are getting more violent. I fear it is only a matter of time before someone is killed. If you know anything—if you have even the faintest idea who might be responsible—tell a professor immediately.”

John thought about McGonagall’s words all night. Should he go to a professor with what he knew? It seemed pointless, considering Ron and Harry already knew all about Irene Adler. They didn’t know about the watch, but how would John explain that? _Excuse me, professor. I thought you should know that my friend Sherlock thinks the poisoner left a secret message in the form of a wristwatch…_

Deep down, John knew he wouldn’t go to a professor regardless. The reason was simple: it was all his fault. He had known that sending Molly in to look for evidence could be dangerous, but he had said nothing. As the oldest of the group, he should have been more responsible. This was his mess, and he would clean it up himself.

Well, not _entirely_ by himself.

* * *

“Irene must have had an accomplice,” he announced at breakfast.

He had been up all night thinking about it. It was too big a coincidence, the real culprit being in the Slytherin common room when Molly just happened to be there and Irene just happened to have an airtight alibi. Irene must have guessed what they were planning when Ron and Harry asked to speak with her and sent someone to keep an eye on her stash.

“Maybe it was a two-person job all along,” John continued. “This other person did the poisoning, Irene sold the antidote, and then they split the profits.”

“A sound theory,” Sherlock said without looking up.

He was reading what appeared to be an astronomy book. This was odd, considering that Sherlock had said just the other day that astronomy was useless, but John was too engrossed in his own thoughts to ask about it. He only felt annoyance at not having the other boy’s full attention.

“We should start by investigating Irene’s friends,” he said. “She’s probably working with another Slytherin girl—maybe that blonde who always follows her around.”

Sherlock grunted vaguely.

“You know, Molly is lying in a coma right now because of you,” John snapped. “You could at least pretend to care.”

Sherlock finally looked at him.

“You think I don’t care?” he asked quietly.

“It certainly doesn’t look like it.”

Sherlock held up his book. “If I didn’t care, would I be wasting my time reading up on bloody _astronomy?_ ”

John opened his mouth, then closed it again.

“Er…are you saying astronomy is going to help you catch Molly’s attacker?” he ventured at last.

“It might.”

Sherlock pulled a wristwatch out of his pocket and set it on the table. John recognized it immediately as the one Molly had been wearing.

“You stole that?” he asked incredulously.

“Of course. How else was I going to examine it properly?”

From behind them came a derisive snort. Both boys turned to see Sally Donovan glaring at Sherlock.

“You know, I hear serial killers often steal personal items from their victims,” she said. “Things like watches and jewelry. They keep them as trophies.”

John was outraged on his friend’s behalf. “You’re not still on about Sherlock being behind all this!” he said. “Look, the poisoner is a _girl_. She has to be.”

“Oh, yeah? What makes you say that?”

John explained about boys not being able to get into the girls’ dormitories. It was extremely satisfying, being able to prove Donovan wrong. However, to his dismay, she only shrugged.

“So he couldn’t get up the stairs,” she said. “Maybe he nicked a school broom and flew in through the window.”

John and Sherlock looked at each other.

“That’s…not entirely implausible,” said Sherlock. He looked as taken aback as John felt.

“Is that a confession?” Donovan asked.

“No, it bloody well isn’t!” John answered. “Don’t you have anything better to do than harass Sherlock?”

Donovan departed with one last suspicious look.

“You didn’t even try to defend yourself,” said John. “Do you want people going around saying you’re the poisoner?”

“It matters very little,” Sherlock said calmly. “Besides, the best way to clear my name is to catch the real culprit. So let’s get back to the case, shall we?”

John sighed. “Okay,” he said. “Explain to me what astronomy has to do with this watch.”

“That would be obvious if you actually bothered to take a look at it.”

Grumbling, John picked up the watch. It was a large, old-fashioned affair, more like his dad’s watch than something an eleven-year-old girl would wear. It was also clearly magical; in addition to telling the time, the face was covered in tiny pictures of the crescent moon, the nine planets circling the sun, and a storm cloud, which he guessed represented the weather.

“Okay, so it tells you what the moon and the planets are doing. But the time is wrong—it’s stopped on twelve o’clock.” John glanced up at the ceiling of the Great Hall, which was currently a beautiful, bright blue. “And it’s wrong about the weather, too, so maybe everything is stuck on the wrong thing. Do you think it’s some sort of code?”

“Obviously,” said Sherlock. John was getting rather tired of that word. “The question is, how do we crack it?”

“Maybe we should focus on finding the accomplice instead,” John suggested.

“That’s what I’m doing,” said Sherlock, in the tone of voice one would use to explain something to a five-year-old. “I’m going to find the accomplice by breaking the code.”

“Wouldn’t it be easier to just interrogate Irene’s friends?”

“Easier, yes. More effective? Unlikely.”

It was the first serious argument in the history of their friendship. Sherlock was convinced the watch was their best bet, but John couldn’t see how decoding secret messages was faster than simply talking to people. In the end, they came to an agreement: John would investigate Irene’s friends while Sherlock focused on the poisoner’s clue.

Even knowing Sherlock’s miraculous talents, John felt like he had a decent chance of solving the mystery first. By evening, however, his confidence had diminished.

He started by investigating the other sixth year Slytherin girls, figuring they would know Irene the best, but it turned out that they were all in Potions when Molly was attacked.

“Was anyone missing from class that day, aside from Irene?” he asked again and again. “Did anyone leave class for a few minutes? Maybe to use the loo?”

“No one.”

“Not that I remember.”

“I didn’t notice.”

“Why should I tell you?”

 _Why did I even bother?_ John thought bitterly. They were Slytherins, and he was a Muggle-born Hufflepuff. Even if one of them had seen something, they weren’t going to tell the likes of him.

At dinner that night, Henry offered to ask around for him. “I hate to admit it, but they might be more open with me—you know, me being pureblood and all.”

John politely turned him down. He had already let one friend get hurt playing detective for him and Sherlock; he wasn’t going to make that mistake again.

He was trying to decide what to do next when a slip of parchment land next to his plate. He looked up just in time to see an owl swoop out the nearest window.

“That’s weird,” said Mike. “I’ve never seen an owl deliver post at dinner.”

John unfolded the parchment and read:

_John,_

_If it’s not too much trouble, could you stop by the Transfiguration classroom after dinner? Ron and I would like to ask you a few questions._

_Harry P._

“Bloody hell!” said Henry, reading over his shoulder. “You weren’t kidding. You really do know Harry Potter!”

“I wonder why he wants to see me and not Sherlock,” John wondered aloud.

“He probably figures you’re more likely to cooperate,” said Mike.

John thought that was a very sound theory. 

Ron on Harry were waiting for him when he reached the Transfiguration room. After the usual pleasantries, Harry launched right into the interview.

“The girl who was attacked last, Molly Hooper—she’s in Hufflepuff.”

John had a feeling he knew where this was going.

“Er, yes, I know,” he said. “She’s a friend.”

“Is she?” Harry raised his eyebrows. “Then maybe you can help us out. We’ve been trying to figure out what she was doing in the Slytherin common room.”

“She was looking for Irene Adler’s stash of potions.”

He couldn’t see any point in lying. Harry must have already suspected the truth, otherwise he wouldn’t have asked John in the first place. Besides, he hadn’t technically done anything wrong…at least, he didn’t think so.

“I see,” said Harry. The famous Auror’s expression was unreadable. “Now, what made her do such a thing?”

“It was Sherlock’s idea. But if you ask him, he’ll say it was _your_ idea, sir.”

“ _My_ idea?” For the first time, Harry looked surprised.

“Yes, sir. That night in the empty classroom, you told us you’d take Irene in for questioning in the morning, right after breakfast. Sherlock said you told us so that we’d know when to search her rooms.”

Ron found this extremely funny. “You’ve got to admire the kid’s nerve,” he laughed.

Harry, on the other hand, didn’t crack a smile. “Molly is still unconscious,” he said quietly. “I hope you boys realize now that this isn’t a game.”

John didn’t have to fake an expression of deep guilt. “We do, sir.”

Harry sighed. “Is there anything else you can tell us?”

John hesitated for only a second. “Actually, there is. Sherlock and I saw Molly right before she was taken to the hospital wing, and Sherlock found…well, a clue.” John felt ridiculous putting it in those terms, like they were playing a game, but he didn’t know what else to call it. “Something that he thinks will lead us to Irene’s accomplice.”

Ron and Harry looked at each other.

“What makes you think Irene had an accomplice?” Harry asked.

John was slightly taken aback. “Well, she was with you two when Molly was attacked, right? So she couldn’t have done it herself. She must have guessed what we were planning when you asked to talk to her, and arranged for someone else…”

He trailed off when he realized that Ron and Harry were both shaking their heads.

“We grabbed Adler as she was leaving breakfast and took her straight to our interrogation room,” said Ron. “She didn’t have time to contact anyone.”

“We eliminated her as a suspect the moment we found out about Molly,” Harry added.

Now John was completely thrown for a loop. He hadn’t even considered that Irene might not be involved at all.

“But…but how did the attacker know that Molly would be searching Irene’s room, if Irene didn’t tell them?” he asked.

“That’s a good question,” said Harry. “Who knew about the plan, aside from you, Molly, and Sherlock?”

“No one. I didn’t tell a soul, and Sherlock wouldn’t tell anyone who didn’t absolutely need to know. And Molly…”

Suddenly, it clicked.

“Bloody hell,” he said, more to himself than anyone. “Why didn’t we see it before?”

“What?” Ron and Harry asked in unison. But John was already bolting down the corridor.

He reached the Hufflepuff dormitory in record time. Mercifully, it was early evening, so most students were hanging out in the common room. He burst through the secret passage and made a beeline for the far corner, where he knew a gaggle of first year girls that usually included Molly would be sitting.

“Molly’s Slytherin friend,” he said between gasps. “What can you tell me about him?”

The girls look at one another, startled.

“I guess he means that second year boy,” one said uncertainly. The others nodded.

“So you know him?” John asked.

“We know _of_ him,” sniffed another girl. “Molly’s the only one who really knows him. How she got to be friends with a Slytherin, I don’t know.”

“Yes, but his _name_. Do you know his name?” John was vaguely aware that he must seem quite mad, but he couldn’t care less.

“James, I think.”

“No, it’s Jim,” said a third girl. “Jim Moriarty.”

John felt a sudden urge to grab the girl and kiss her, but he resisted it.

“Thank you!” he said. Then he was off again.

He was halfway down the corridor before he realized he had no idea where the Ravenclaw common room was. It turned out to not matter, for at that moment the person he was looking for came around the corner, nearly running straight into him.

“I’ve solved it!” Sherlock said triumphantly. He waved the watch in John’s face. “I’ve cracked the code! We’ll know who attacked Molly by midnight tonight!”

For the first time in days, John grinned.

**Notes for the Chapter:**

> Once again, I’d like to thank all of my lovely readers for sticking with me. Sorry for the long, unexpected hiatus between chapters seven and eight. Updates should be more frequent now that I’m out of school.
> 
> By the way, if you want a sneak peek at each chapter a day or two early, you should [follow me on Tumblr.](http://www.somenerdygirl.tumblr.com)


	10. Another Midnight Meeting

**Summary for the Chapter:**

> Two prodigies finally meet.

As far as Sherlock was concerned, the day’s events proved that he was right to begin with: astronomy was useless.

“It was nothing more than a distraction,” he told John, disgusted. “Once I rejected my initial hypothesis, that the position of the planets was significant in itself, the rest was child’s play.”

The rest of his explanation went well over John’s head, but he didn’t care much. All that mattered to John was the bottom line, which really was simple. By moving the watch’s hands into a certain position, Sherlock opened a secret compartment in the back of the watch. Inside was a tightly-folded scrap of parchment.

The message was short and blunt: _Friday. Midnight. Room of Requirement. Come and play, Sherlock. Just you and me._

John stared at his friend.

“Why did he leave a message for _you?_ ”

“Obviously, he heard about our investigations,” said Sherlock. “He must have recognized that I was the brains of the operation.”

“Oy! Remind me who found out about Jim Moriarty!”

“Yes, yes, that was very clever. Remind me to pat you on the back later.”

John wanted to go straight to Harry and Ron, but Sherlock insisted on waiting.

“Our evidence is entirely circumstantial at this point,” he said. “If we play along with Moriarty’s little game, he might reveal more.”

“But Ron and Harry could help us. Eight eyes are better than four, right?”

“The message stresses that I must come alone.”

For the first time, John really began to doubt Sherlock. Not that he believed Donovan’s rubbish theory about him being behind the attacks, of course. But it seemed like Sherlock was more interested in solving the puzzle, as he put it, than in actually seeing the culprit brought to justice. First, he wasted a day decoding the watch while John proved that doing so was unnecessary. Now he wanted to confront Moriarty himself instead of calling in the professionals. John suspected he just couldn’t pass up the chance to talk one-on-one with a genuine criminal mastermind.

Once again, they had to compromise. John agreed not to tell anyone about the meeting, on the condition that Sherlock allowed him to come along as backup.

“All right, but stay hidden, and don’t come out unless I give you the signal,” Sherlock said testily. “He might not show his face if he sees I’m not alone.”

“Deal.”

The first time John and Sherlock had sneaked out for a little midnight detective work, they had learned a few things, but not nearly enough. The second time had been a complete disaster. John fervently prayed that the third time would be the charm. He was ready for this adventure to be over.

* * *

They met a full hour early, just to make sure they got to the Room of Requirement before Moriarty. This was partly so that John would have time to hide, and partly to throw Moriarty off if he was trying to lead Sherlock into a trap.

John had never been in the Room of Requirement before, though he knew its reputation well.

“How do we get in?” he whispered.

“We need a place where I can talk to Moriarty undisturbed,” said Sherlock. “We also need a way for you to listen in without Moriarty knowing. Just picture a room like that in your head and copy me.”

He began pacing back and forth across a small stretch of corridor, hands clasped behind his back. John mimicked the younger boy, though it made him feel rather silly.

 _A place where Sherlock can talk with Moriarty, and I can listen in without Moriarty knowing,_ he thought. _So we’ll need some sort of screen or—_

“Ah!” cried Sherlock. “Here we are!”

John blinked. There was a door to his right that definitely hadn’t been there a moment before.

 _Now,_ this _is a secret passage_ , he thought as he followed Sherlock into the room.

They found themselves in a cozy little chamber furnished with two armchairs and a fireplace. It looked rather like a miniature version of the Hufflepuff common room, except without all the yellow and black. John had been expecting something grander, but he supposed anything more would be overkill for a meeting between two people.

“Where am I going to hide?” he asked, looking around the room.

“I expect you’ll find that mirror opens up,” said Sherlock, nodding to a full-length mirror in the corner. “I was envisioning something of the sort.”

John pushed gently on the mirror’s frame. Sure enough, it swung forward like a door, revealing a room no bigger than a broom cupboard. John stepped inside and pulled the mirror back into position. From this side, he had a perfect view of the larger room.

“Can you see me?” he called.

“No, but I can hear you loud and clear,” said Sherlock. “You’ll have to be completely still once Moriarty arrives.”

The next half hour passed by excruciatingly slowly. John would have been tempted to take a nap if his hiding place had been large enough to lie down in. (Sherlock insisted that he stay behind the mirror, in case Moriarty turned up early.) Sherlock himself showed no sign of drowsiness. He sat bolt upright in his armchair, with his fingers steepled under his chin and his gaze fixed on the hearth. It was almost creepy how little he moved.

At a quarter to midnight, Moriarty arrived.

He looked…like any other twelve-year-old. John felt surprised, then realized that was ridiculous. Evil people would never get away with anything if they looked evil. All the same, he couldn’t wrap his head around the idea that this ordinary-looking boy had poisoned three people. His youth alone was disconcerting.

For a split second, Moriarty looked startled to see that Sherlock had gotten to the Room of Requirement first, but only John would ever know that. By the time Sherlock turned his head, the look of surprise had been replaced with a bland smile.

“My, aren’t we punctual!” said Moriarty.

Maybe John’s perception was colored by what he already knew of the boy, but he thought there was a sinister glint in his eyes.

Sherlock remained completely expressionless.

“James Moriarty,” he said.

Moriarty bowed.

“Sherlock Holmes,” he said. “I’ve been wanting to meet you for ages.”

“Likewise,” said Sherlock. “Though for entirely different reasons, I imagine.”

“Oh, I don’t know about that.” Moriarty took a few steps closer. “You came here to study me, didn’t you?”

“To stop you,” said Sherlock.

“To _study_ me!” Moriarty repeated sharply. The speed with which he shifted from one emotion to the next was terrifying. “If stopping me was really your primary concern, you would have gone to Saint Potter the minute your little Hufflepuff friend told you my name.”

Behind the mirror, John shuddered. It was more than a little disturbing to hear his own thoughts coming out of Moriarty’s mouth.

Sherlock stared at Moriarty for a moment before responding.

“You don’t give a damn about blood purity,” he said. “You didn’t even plan for the first victim to be a Muggle-born.”

“I would have done, if I’d known what a panic it would cause,” Moriarty said, grinning.

“You targeted a Muggle-born the second time, to increase the hysteria.”

“Obviously.”

“And you’re not making any money off of this.”

“Not a Knut.”

“So it’s all just a game,” Sherlock concluded. To John’s relief, he sounded appropriately disgusted. “This is _fun_ for you.”

“And for you,” said Moriarty.

Sherlock’s expression was unreadable. “You think so?”

“I know so.” Moriarty leaned in. “I’ve been watching you, Sherlock Holmes. Almost since you stepped off the Hogwarts Express. You’re brilliant. You’re like me. That’s how I knew you must be as bored as I was.”

There was a long pause. John’s heart sank as he realized that Moriarty was right. Sherlock was bored out of his skull most of the time—bored with classes, bored with classmates, bored with life. The only thing John had ever seen him show real interest in was solving the mystery of the poisoned students.

 _What will he do with himself when Moriarty is behind bars?_ John wondered. 

From the look on Sherlock’s face, John knew that he was thinking the same thing. And Moriarty saw it, too.

“What do you want from me?” Sherlock asked quietly.

“Isn’t it obvious?” asked Moriarty. “I want you to keep playing the game.”

“You want me to join you.” Sherlock didn’t phrase it as a question.

“If you keep playing the hero, then the game will be over soon. I’ll have to kill you.” Moriarty said this as matter-of-factly as if he were explaining the rules of Cluedo. “But if you come over to the dark side, we can have fun together for years. Neither of us will ever be bored again. And they’ll never catch us, because who else is clever enough?”

In the silence that followed this little speech, John could hear his heart beating.

“Molly Hooper is a friend of mine,” Sherlock said at last.

Moriarty threw back his head and laughed.

“Your _friend?_ You’re Sherlock Holmes! You don’t have _friends._ You have enemies and pets.” He adopted a posh accent that was a perfect parody of Sherlock’s. “Fetch, Molly! Good dog, Molly. And good dog, John, getting me that name. Remind me to pet you later!”

Moriarty shook his head. “A man can’t be friends with a mutt, Sherlock. The only person in this school—in this _world_ —who could really be your friend is me. So what do you say?”

He held out his hand. Sherlock stared at it for a moment, then shifted his gaze to Moriarty’s face.

“Two words,” he said. “Vatican cameos.”

John was out from behind the mirror in a flash, his wand pointed directly at Moriarty’s heart.

“STUPIFY!” he screamed.

John was an exceptional dueler. He didn’t have Sherlock’s encyclopedic knowledge of spells, but he had great aim and concentration. Most importantly, he was fast.

Moriarty was faster.

Afterward, John was never sure what exactly had happened. One moment he was bursting out of hiding, and the next he was lying on the floor.

“John! JOHN!”

Sherlock’s face appeared above him, looking even paler than usual. In his dazed state, it took John a while to realize that he was seeing something new: Sherlock afraid.

“You had your chance, Sherlock.” Moriarty’s voice came from somewhere in the distance. “Now I’ll have to destroy you.”

He paused.

“And your little dog, too.”


	11. A Risky Ruse

**Summary for the Chapter:**

> John offers himself up as bait, but he's not the only one setting a trap...

“We’re contacting Ron and Harry right now,” John said when he’d recovered enough to speak.

For once, Sherlock didn’t argue. They went straight to the Owlery, and within half an hour, Sherlock was attaching a letter to his tawny owl’s leg. He had charmed the envelope to say URGENT in flashing red letters.

“What do we do until they get here?” John asked as they watched the owl fly off.

“I am going to learn everything I can about James Moriarty, and you are going to go back to your dormitory and rest,” said Sherlock.

John snorted. “Not bloody likely.”

Sherlock frowned. “Actually, you’re right,” he said. “Moriarty will be expecting that. You’d better take my bed in Ravenclaw Tower—or better yet, go back to the Room of Requirement. If you ask it to protect you, Moriarty won’t be able to get back in.”

“That’s not what I meant!” said John. “I’m not quitting just because I got Stunned for a second.”

“No, you’re quitting because Moriarty is out to get you. Or did you miss his parting words?”

Sherlock’s face was hidden in shadow, but in the moonlight, John could see the boy’s hands clutching the window ledge. He had never been more tense.

“You’re really worried about me, aren’t you?” said John, oddly touched. Sherlock didn’t respond.

John sighed. “I’m not letting you go after Moriarty on your own,” he said. “He threatened us both, remember? We do this together, or not at all.”

“Fine,” said Sherlock. “But you’ll need sleep first.”

“So will you.”

“I don’t need as much sleep as other people.”

They argued about the logic of this statement all the way to Ravenclaw Tower.

* * *

The next morning, Professor Longbottom caught John as he was entering the Great Hall and led him to an unused classroom. Harry, Ron, and Sherlock were already there.

“Do you have any proof?” Harry asked when the boys had finished their story.

“Nothing concrete,” Sherlock admitted. “But it all fits. He’s the only person who knew Molly was going to be in the Slytherin dormitory. Find out what class he had at that time—I guarantee you he didn’t turn up.”

“And Sherlock and I can testify against him,” John added. “We both heard him confess everything.”

“I believe you,” said Harry. “But the Ministry of Magic isn’t going to throw a twelve-year-old in Azkaban on the word of two kids.”

“What do you have to say about this, Neville?” Ron asked Professor Longbottom. “You must know the Moriarty kid.”

“I can testify that he’s frighteningly intelligent and a bit creepy,” said Longbottom, “but that’s all.”

“And that’s not enough,” said Harry. “We need hard evidence, or this will all be a waste of time.”

An idea popped into John’s head—a wild, terrifying idea. He spoke up before he had a chance to think twice about it.

“What if you saw him poison someone with your own eyes?”

The others looked at him, startled.

“That would do, obviously,” Ron said after a moment. “But he’s not going to try anything right in front of us, is he?”

“Maybe you could be hiding nearby,” said John. “All you’d need is the right bait.”

Sherlock sprang to his feet.

“John, no!” he shouted. “It’s too dangerous!”

Of course, his friend had deduced exactly what he was thinking.

“I’ll be fine,” said John. “Moriarty can’t hurt me too badly with these two nearby.”

Longbottom looked nearly as worried as Sherlock, but Ron looked more impressed than anything else. Harry’s expression was the hardest to read.

“I appreciate your vote of confidence, John,” he said, “but this could still be dangerous. Are you sure you want to take such a risk?”

The image of Molly lying unconscious on the floor of the Slytherin common room came unbidden into John’s mind.

“Yes,” he said. “I’m sure.”

* * *

John felt less nervous approaching Moriarty than he had approaching Irene Adler. He knew that was absurd—the worst Irene could be accused of was greed, whereas Moriarty had nearly killed three people. But his outrage seemed to leave no room for any other emotion. The languid smile Moriarty gave him as he walked up to the Slytherin table only made him angrier.

“May I help you with something?” Moriarty asked.

“It’s all over.” John spoke quietly so as not to be overheard. “I sent an owl to Harry Potter, and he agreed to meet with me tonight. I’m going to tell him everything.”

Moriarty’s smile only widened.

“Oh, really?” he said, not bothering to keep his voice down. “Thank you for warning me. That’s very…fair of you.” He turned back to his lunch.

 _That’s it?_ thought John. No threats, no theatrics, no monologue about how he would get his revenge? Not even another scathing remark about John being Sherlock’s dog?

After standing there awkwardly for several seconds, John went back to the Hufflepuff table. A trap had just been set, but he wasn’t sure who was the hunter and who was the prey.

* * *

The following eight hours were the most stressful of John’s life. Every second, he was expecting Moriarty to leap out of the shadows with his poisoned rag. Every object he had reason to touch was suspect; he didn’t eat a bite at dinner.

Every once in a while, he would catch a glimpse of Ron or Sherlock or Professor Longbottom trailing him. Harry, he supposed, was hiding under his Invisibility Cloak. This made John feel a bit safer, but he couldn’t help wishing his allies were a bit closer. How much damage could Moriarty inflict before they got within Stunning distance?

 _Don’t whinge,_ he told himself sternly. _This was your idea._

To make matters worse, Sherlock showed up at dinner looking like he’d run headlong into the Whomping Willow. John all but sprinted to the Ravenclaw table.

“What happened?” he asked frantically. “Was it Moriarty? Did he—”

“Of course not,” Sherlock cut in. “Moriarty doesn’t fight with his fists. It was Sebastian Moran. He cornered me in the loo. Don’t worry,” he added at the look on John’s face. “For once, his minions weren’t there to hold me down, so I got away before he could do much damage.”

John’s fists clenched. On any other day, he would have set off to find Moran without another word, but they had bigger problems at the moment.

“Put some ice on that eye,” he told Sherlock before going back to his table.

After dinner, he started walking in the direction of the Astronomy Tower. They had all agreed this was the best route. The tower was somewhat remote from the rest of the castle, which was advantageous for a couple of reasons. It was plausible that Harry would ask John to meet him there, and the long walk gave Moriarty plenty of time to make his move.

John reached the Astronomy Tower without incident. With nothing else to do, he climbed the stairs to the top of the tower and waited.

As the minutes ticked by, John began to worry for an entirely different reason. What if Moriarty didn’t turn up? What if he saw right through John? What else could they do?

“I don’t think he’s coming.”

To his eternal shame, John shrieked like a five-year-old girl.

“Oh, sorry!” said the disembodied voice. There was a rustle of fabric, and Harry Potter appeared before him, clutching a silvery cloth that could only be the Invisibility Cloak.

Harry kindly ignored John’s jumpiness. “You might as well go back to your dormitory,” he sighed. “I’ll walk you there, just in case.”

They descended the stairs in silence, each lost in their own thoughts. John had never dreamed he could feel so disappointed about _not_ being assaulted.

“Looks like he’s not coming,” Harry called as they exited the tower. “Best call it a night.”

There was no response.

Harry frowned. “Ron? Neville?”

Silence.

Harry pulled John back against the wall. “Something’s wrong,” he whispered. “Ron and Neville should be here.”

“And Sherlock,” John whispered back. “I’m sure he came along, whether they told him to or not.”

Harry consulted the Marauder’s Map and groaned.

“Damn,” he said. “Something’s definitely happened.”

He tilted the map for John to see. Dozens of black dots were congregated around a spot in the dungeons, so many that the names jumbled together and became indecipherable. It looked like ants swarming over a breadcrumb.

John swore under his breath. He could only think of one reason why that many students would be in the corridors at this hour. Without another word, he and Harry began running towards the dungeon.

 _Sherlock,_ John thought. _He went after Sherlock first. Of course he did. He must have lured him down to the dungeons somehow and…Oh, God, please don’t let him be…_

Before he had even finished thinking it, the answer to his prayer came bounding around the corner and crashed right into him.

“Argh! John, didn’t your mother ever tell you not to run indoors?”

John had never been more relieved to hear himself insulted. “Sherlock! You’re okay!”

“For the moment,” Sherlock said grimly.

“What do you mean, for the moment? What happened?”

“There’s been another poisoning,” said Ron, coming up behind Sherlock. Professor Longbottom wasn’t far behind.

“Who was attacked this time?” John asked.

The other three looked at each other, as though trying to decide who should break the news. In the end, it was Longbottom who spoke.

“Jim Moriarty.”


	12. Continuing Complications

**Summary for the Chapter:**

> Moriarty is a stereotypical Slytherin, and John is a true Hufflepuff (who would fit in well enough in Ravenclaw).

**Notes for the Chapter:**

> For an apology for the months-long hiatus, please see [my Tumblr.](http://www.somenerdygirl.tumblr.com)

As usual, Sherlock took charge of the situation before anyone could object.

“John, come with me,” he said, and began marching off.

John looked at the adults.

“Go ahead,” Harry sighed. “Whatever Sherlock has planned, I don’t have the energy to try and stop him right now.”

“Maybe you can keep him from doing anything too outrageously dangerous,” Longbottom added.

John thought the professor was probably overestimating his influence. Nevertheless, he followed Sherlock down the corridor.

He was still trying to wrap his head around this latest turn of events. How could _Moriarty_ have been attacked? Did this mean he had an accomplice, who had turned on him? Or had he poisoned himself to throw the Aurors off his scent?

John was leaning towards the latter. It seemed like the sort of clever, mad thing Moriarty would do. But Ron and Harry weren’t stupid, and they already had plenty of reason to suspect Moriarty. Surely, this would only delay his arrest for a little while. Unless…unless he had another trick up his sleeve…

“Have you got any parchment?” Sherlock asked abruptly.

John came out of his reverie with a start.

“What?”

“Parchment,” Sherlock repeated. “Or maybe a journal? A book you don’t like too much? Anything you can write on?”

“Er, not on me.”

Sherlock cursed under his breath. Before John could ask why he needed something to write on, the other boy took off again. Grumbling, John followed him all the way to Ravenclaw Tower.

He waited in the common room while Sherlock went upstairs, presumably to disturb all of his classmates by rummaging through his trunk in the middle of the night. Eventually, he returned with a pocket-sized notebook.

 _“Annecto verbius,”_ said Sherlock, tapping the book with his wand. It glowed blue for a moment, and then…nothing. However, Sherlock seemed satisfied.

“Keep it nearby at all times,” he said, handing the book to John. “Against your body, if possible. It will get warm when I send you a message.”

John tucked the notepad into the waistband of his trousers. Though not exactly comfortable, it was discreet: his robes hid the bulge completely.

“And I need this, because…?”

“You’re going to have to be my eyes and ears once I’m locked up. This way, I can tell you what to look for, and you can report back.”

John looked up, startled.

“What do you mean, _once you’re locked up?”_

“Obviously, when Moriarty accuses me of poisoning him, the adults will have to act.”

John groaned. Of course. That was Moriarty’s final trick: to frame Sherlock for his crimes. It was so simple, he felt like an idiot for not working it out on his own.

“But you have an alibi,” he said. “You were with Ron and Professor Longbottom, weren’t you?”

Sherlock shook his head. “Not with them so much as near them. We were all shadowing you from different positions. Theoretically, I could have slipped down to the dungeons to poison Moriarty and slipped back before anyone noticed I was gone.”

“Ron and Harry won’t believe that.”

“Maybe not, but they can’t appear biased. They’ll have to take me into custody, at least until my name is cleared.”

Sherlock looked John in the eye, but not in his usual, unnerving, Sherlock-y way. For once, he wasn’t looking only to deduce.

“John,” he said, “it’s up to you now.”

* * *

When Sherlock didn’t appear at breakfast the next morning, John told himself not to panic. Sherlock had anticipated this. Everything was under control. In fact, his absence didn’t even mean that he’d been arrested, necessarily. He might have simply decided to skip breakfast in favor of working on the case—he never seemed to eat, anyway.

Then Sally Donovan came by to dash this hope to pieces.

“I just saw Harry Potter and Ron Weasley leading Holmes into the headmistress’s office,” she informed him.

John had been raised to believe one should never hit a girl, but the smug look on Donovan’s face was seriously tempting him.

“Sherlock was framed,” he said.

Donovan’s expression became pitying, which was somehow even worse.

“I warned you, didn’t I?” she said. “I told you to stay away from that freak.”

“Yeah,” said John. “And thank God I didn’t listen.” Then he walked away before she could respond.

His first impulse was to burst into McGonagall’s office and defend his friend’s honor, but he nixed that plan after picturing the look on McGonagall’s face. With nowhere else to turn, he walked down to the greenhouses, where he found Professor Longbottom watering the Mandrakes.

“Sally Donovan told me she saw Ron, Harry, and Sherlock going into the headmistress’s office,” he said without preamble.

Longbottom set his watering can down with a sigh. “Yes, I expect she did.”

Usually, the professor had an almost Buddha-like calm about him when he was at work, but today he looked haggard and worried. John regretted bothering him, but not enough to leave without getting any information Longbottom could provide.

“So Sherlock was right,” said John. “Moriarty is trying to pin it all on him.”

“He’s saying that Sherlock attacked him last night,” Longbottom confirmed.

“But it’s his word against Sherlock’s. That’s not enough to convict him, is it?”

“It wouldn’t be on its own. But three different paintings told Harry and Ron that they saw Sherlock going down to the dungeons right before Moriarty was found.”

John supposed this was the moment when most people would begin to have serious doubts about their friend. He brushed the thought away immediately.

“It’s a trick,” he said. “Moriarty tricked the paintings somehow, or—or made them lie for him.”

“That’s what Sherlock thinks,” said Longbottom. “He has several theories as to how it might have been done, but without any hard proof, I’m afraid that’s not going to do him much good.”

 _This is what Sherlock meant when he said it was all up to me now,_ John thought. _I have to find the proof. But where do I even begin?_

“You…you don’t believe Moriarty, do you, professor?” he asked.

“No, I don’t,” Longbottom said without hesitation. “But others will. I’m guessing Miss Donovan didn’t come to you because she was worried about Sherlock’s wellbeing.”

John recalled Donovan’s smug face, and felt the urge to punch something all over again.

“That _cow,”_ he spat. He was too angry to care that he was talking to a teacher.

“John, please, try to look at it from her point of view,” said Longbottom. “Sherlock is a pureblood, and a lot of his relatives were in Slytherin. Everyone knows he’s a genius, and…well, even you have to admit, he’s not always pleasant to be around. Moriarty, on the other hand, is a half-blood, and he’s kept a low profile up till now. If you only knew both boys in passing, who would you think was telling the truth?”

John said nothing, but they both knew the answer.

Longbottom patted him on the shoulder. “Don’t worry. Something similar to this happened to Harry in our second year, and it all got sorted out in the end.”

John nodded, but all he could think about was Moriarty’s words echoing in his head:

_You had your chance, Sherlock. Now I’ll have to destroy you._

* * *

He was on his way to Transfiguration when he felt it: a burst of warmth against his abdomen. He whipped the notebook out of his waistband so fast that he nearly gave himself an extremely awkward paper cut. Written on the front page, in Sherlock’s trademark scrawl, was a single sentence:

_Watch who talks to Moriarty._

* * *

Moriarty was released from the hospital wing the next morning. It soon became obvious that Sherlock’s instructions would be easier said than done: _Everyone_ wanted to talk to Moriarty about his supposed brush with death. A small crowd surrounded him all through breakfast, asking him questions, telling him how glad they were that he’d survived, and offering to get him more sausages. It made John’s blood boil.

“You need to calm down, mate,” Mike whispered. “You’re not going to make him confess by glaring at him.”

John said nothing. If he explained about Sherlock’s message, Mike would want to help, and John was more determined than ever to not let anyone else get caught up in this mess.

“Blimey,” said Henry. “He doesn’t look happy, does he?”

John followed Henry’s gaze. Sebastian Moran had just entered the Great Hall, looking even surlier than usual. John didn’t think much of it, until he realized that Moran was heading straight for Moriarty.

Moran cut through the crowd like a shark through a school of fish. As people dived out of his way, Moriarty’s dismayed face emerged for a moment before disappearing again behind Moran’s bulk.

John stood up to get a better view. Moran was bent over, whispering something in Moriarty’s ear. The other boy looked around before furiously shaking his head. Even from across the Great Hall, the message was clear: _Not here._

John had never seen Moriarty look so cagey. What had Moran said to him?

The question ran on a loop in his head all afternoon. Then, halfway through History of Magic, it clicked.

“Sorry-professor-I-have-to-go-to-the-loo!”

Professor Binns, who was in the middle of a particularly mind-numbing lecture on the Broomstick Tax of 1784, didn’t even look up as John bolted out of the room. But a few of his classmates were rather startled.

Minutes later, he burst into the classroom that Ron and Harry had transformed into a temporary office.

“Polyjuice Potion!” he gasped.

The Aurors looked at him with mingled surprise and bewilderment.

“Er, what?” Ron asked.

John took a few much-needed, deep breaths before launching into his explanation.

“The day before yesterday, Sebastian Moran cornered Sherlock in the loo and beat him up. What if he pulled out some of Sherlock’s hair? Moriarty could have put him up to it—offered him money or the answers to his next Potions exam or something. Then Moriarty put the hair in a Polyjuice Potion. It was him the portraits saw going down to the dungeons, not Sherlock.”

“Polyjuice Potion takes weeks to brew, John.” Harry said this cautiously, as if trying to burst John’s bubble as gently as possible.

“But you add the hair last, right?” said John. “Moriarty told Sherlock he’d been watching him almost since he got off the Hogwarts Express. He might have been planning this for just as long.”

There was a slight pause.

“What do you think?” Ron asked Harry.

“It’s more plausible than your evil twin theory,” he said.

“Loads of people have twins!” Ron huffed. “And that was just a passing thought, anyway. Let it go.”

“All right,” said Harry. “I guess we should have a talk with this Moran.”

“He’s probably still in the Great Hall,” said John. “If we hurry, we can catch him before—”

Harry cut him off. “By _we_ , I meant Ron and me.” He looked at John sympathetically. “I’m sorry. I know you want to help, but it’s just too dangerous.”

John protested, but it was no use. The adults were convinced that allowing him and Sherlock to help with the case had been a mistake, and one that they weren’t going to make again. Thus, John found himself standing alone in the corridor, at a loss for what to do next.

The thought of going back to History of Magic was unbearable. The common room would be empty at this time of day, and he wasn’t sure he wanted to be alone. Most other places would leave a slight possibility of running into Donovan again. In the end, there was only one option that didn’t sound torturous.

He headed for the hospital wing.

* * *

Molly looked terribly small in the large hospital bed. A lump formed in John’s throat as he watched her motionless form.

“We know who did this to you, Molly,” he said softly. “And we’re going to make him pay. I promise.”

Behind him, the door to the hospital wing creaked open. John cringed, fully expecting to be accosted by an outraged Madam Pomfrey. Instead, he found himself face-to-face with none other than Irene Adler.

“What are _you_ doing here?” he asked.

Irene flushed. “I just came to see how Molly is doing!” she said angrily. “I tutored her in Potions, and…and…”

Irene looked past John at Molly, and her words seemed to leave her.

There was a tense pause. Then, sighing, John offered Irene his chair.

“Thank you,” she whispered.

John felt bad for snapping at the girl. He knew his anger was misdirected. Irene Adler was an opportunist, but she was no murderer. She wasn’t the reason Molly was in a coma.

“She’s such a sweet girl,” said Irene. “Why would anyone do this?”

“For fun,” John said bitterly. “For the power trip. For the thrill of getting away with it.”

Irene turned to him, and there was a fierceness in her expression that he had never seen there before.

“You know who it is, don’t you?” she said.

John nodded.

“Tell me.”

A day ago, John would never have imagined himself confiding in Irene Adler. But now Sherlock was gone, and almost everyone believed he was a criminal, and if anyone would believe the truth, it was Irene. The words poured out of John like a waterfall.

Irene listened intently. When he finished, she sat in silence for a long time before saying anything.

“If Moran confessed to getting Sherlock’s hair for Moriarty, would that be enough to sort everything out?” she asked.

“I don’t know,” said John. “But it would cast suspicion on Moriarty, at the very least, and that’s better than nothing, right?”

“Quite right.”

Irene stood up.

“Well then,” she said. “What are we waiting for? Let’s find Moran.”


	13. Consulting Criminals

**Summary for the Chapter:**

> John has a new ally, whether he wants her or not.

Just as John was getting used to flying solo, the reins were unceremoniously snatched out of his hands. Irene acted as though this had been her investigation all along. Like everything she did, it was simultaneously annoying and awe-inspiring.

“Are you sure this is necessary?” John asked as he followed her down the corridor. “I mean, I appreciate that you want to help, but Ron and Harry are going to question Moran.”

Irene turned to look back at him, one eyebrow arched.

“And who do you think Moran is more likely to open up to?” she asked. “Harry Potter, or me?”

She had a point. Still, John worried that even Irene’s charms wouldn’t be enough to make Moran talk. Moriarty was obviously the brains of the operation, but that didn’t mean Moran was a total idiot.

“Oh, John,” said Irene, “you have a lot to learn.”

“You think I’m overestimating him?”

“No.” She winked. “I think you’re underestimating me.”

* * *

A few hours later, Sebastian Moran entered the Room of Requirement. In one hand, he held a note written in an elegant script. In the other, he held his wand like a dagger.

“Ah, Sebastian!” Irene gave him her most dazzling smile. “You’re a bit late, but I forgive you.”

Moran slowly looked around the room, taking in the fire on the hearth, the looking-glass hanging in one corner, and the various other homely touches.

“I hope my directions were clear enough,” Irene continued. “I realize this room isn’t easy to find, but that’s what makes it so perfect for this meeting. No one can possibly overhear us.”

“You said you wanted to discuss business,” said Moran, holding up the note. “What business?”

“Right to the point. I like that.” Irene settled back in an armchair. “Very well, Mr. Moran. I heard a delicious little rumor about you, and I wanted to find out it if it was true.”

Moran sat down across from her, still looking wary.

“What rumor?”

“That you’re an entrepreneur as well as a bully. You’d rough up your own mother if the price was right.”

A flicker of pride crossed Moran’s face.

“Who told you that?” he asked.

“So it’s not true, then?” Irene looked disappointed. “Ah, well. It did seem farfetched, a first year having enough clout to—”

“Hang on!” Moran leaped to his feet. “I didn’t say it wasn’t true!”

Irene smiled. “So you can help me?”

“Give me a name and a price, and we’ll see.”

“All in good time, Mr. Moran. Before we go any further, I’ll need some references.”

_“References?”_

“Of course.” Irene returned his incredulous stare with a look of mild surprise. “I’m not going to throw my hard-earned Galleons away on the word of a single first year. How do I know you’ll come through?”

“I can do it.”

“But. How. Do. I. Know?” Irene repeated. “Can anyone vouch for you?”

Moran chewed on his lower lip. Seconds ticked by on the clock on the mantelpiece.

“Moriarty,” he said at last. “Ask him.”

“Jim Moriarty?” Irene raised her eyebrows. “That quiet little second year boy? Oh, now I know you’re having me on!”

Moran snorted. “’Quiet little boy’ my arse. He paid me five Galleons to beat the snot out of Sherlock Holmes.”

“Sherlock Holmes?” Irene repeated. “What has Moriarty got against him?”

“No idea. But between you and me, I think there’s something freaky going on there.”

“Freaky how?”

Moran leaned forward, answering in a conspiratorial whisper. Apparently, some of Moriarty’s love of theatrics had rubbed off on him.

“He asked me to bring him some of Holmes’s _hair.”_

“Fascinating,” said Irene. “Did he say what he wanted it for?”

Moran shook his head.

“That _is_ rather freaky.”

There was a pause.

“So…” said Moran. “Is that enough for you? Do I get the job?”

Irene smiled wider than ever.

“Hmm, a very good question.” She looked over her shoulder. “What do you think, John?”

John stepped out from behind the looking-glass.

“I think that’s plenty,” he said.

He pressed a button, and the magical tape recorder in his hand shut off with a click.

When he saw the look on Moran’s face, he wished he’d brought a camera as well.

“You tricked me, you bitch!”

Moran lunged for Irene. John fumbled for his wand, but Irene was already prepared. Moran was down for the count before he knew what hit him.

“Idiot,” said Irene. “That was so easy, it almost wasn’t fun.”

“What should we do with him?” John asked, prodding Moran with his toe.

“Leave him here, I suppose. We got what we needed out of him.”

“But what if he warns Moriarty?”

“And admit to ratting him out? I don’t think even Moran is that stupid.”

In the end, they left Moran lying on the floor, unconscious but unbound. They had bigger fish to fry.


	14. The Final Feint

**Summary for the Chapter:**

> Things wrap up a little too neatly.

If John lived to be a hundred, he didn’t think he’d ever feel more proud than he did playing his recording for Harry Potter and Ron Weasley.

“Have you thought about what you want to do after Hogwarts?” Harry asked when it was over. “Because you have the makings of a fantastic Auror.”

“Thank you, sir,” said John, blushing.

Actually, he’d often thought that he’d make a good Healer. But if the Boy Who Lived said he was Auror material, maybe that was worth looking into.

“Is this enough to put Moriarty away?” Irene asked.

“That’s for the court to decide,” said Ron. “But it’s definitely enough to take him into custody.”

“And release Sherlock,” John put in.

“Of course. In fact…” Harry fished a key out of his pocket and handed it to John. “Sherlock is in our temporary office. Why don’t you let him out while Ron and I fetch Mr. Moriarty?”

John turned to Irene. He was itching to see Sherlock, but it seemed ungrateful to leave without acknowledging the girl who’d helped him so much.

“Er…thanks,” he said.

“Oh, the pleasure was all mine. Besides…” She smiled wickedly. “I have a feeling it will prove useful one day, having Sherlock Holmes in my debt.”

John shook his head. He still didn’t know what to make of Irene Adler, and he was beginning to think he never would. He was strangely okay with that.

He all but ran to Ron and Harry’s office, then froze with his hand on the doorknob. What should he say when he opened the door? Maybe he should think of something really witty or cool, like…er…

“Oh, for Merlin’s sake, John!” Sherlock called. “Just open the door.”

Sighing, John obeyed.

The classroom looked like any other, except for the addition of a couch, no doubt conjured by Ron or Harry to make their prisoner more comfortable. There lay Sherlock, his pale eyes fixed on John.

“Well?” he asked.

“You’re in the clear,” said John.

Slowly, an enormous grin spread across Sherlock’s face.

“You did it!” he said. “You solved it!”

John had been wrong. _This_ was the proudest moment of his life.

Sherlock insisted on waiting for the Aurors to return with Moriarty. Not that John protested; as much as he wanted to put this whole business behind him, he also wanted to see justice served.

They didn’t have to wait long. Minutes later, Ron and Harry came around the corner, dragging a handcuffed Moriarty between them. The latter was strangely quiet, though he looked at John and Sherlock as though he’d like nothing more than to skin them alive.

 _I guess it’s harder to think of witty lines when you’re in chains,_ John thought smugly.

“He came quietly,” Ron told them as Harry locked Moriarty in the office. “I guess he’s clever enough to know when the jig is up.”

John sighed in relief. Then he noticed that Sherlock was frowning.

“What’s wrong?”

“I’m not sure yet,” said Sherlock, “but I have a few theories.”

John chuckled nervously. “What are you on about? We won! We solved the case, and Moriarty is in handcuffs.”

“Hm,” was all Sherlock said in response.

* * *

John couldn't decide which part of dinner that night was the best: the empty chair at the Slytherin table; everyone treating him and Sherlock like heroes; or the look on Sally Donovan’s face when Lestrade made her apologize to both of them.

“To John and Sherlock, the Boys Who Deduced!” said Mike, raising his goblet.

“And to Irene Adler, the Girl Who Seduced!” someone down the table added.

That got a big laugh. John joined in, but only after checking to make sure that Irene wasn't within earshot.

“Hey, John,” said Henry, nudging him. “Look who’s here. Come to congratulate you publicly, I imagine.”

Harry Potter had quietly entered the Great Hall. John sat up a little straighter, thinking Henry was probably right about his purpose. But Harry didn’t stop at the Hufflepuff table, didn't even pause as he passed John. He went straight to the teacher’s table, where he whispered something in Professor McGonagall’s ear. The color drained from the headmistress’s face.

“Ladies and gentlemen!” she said, leaping to her feet. “We have a situation. If anyone knows the current whereabouts of Jim Moriarty, please tell an adult _immediately.”_

For about three seconds, there was absolute silence. Then all hell broke loose.

“You said they caught him!” a first year shrieked at John. “You said he was locked up!”

“He is!” said John, stunned. “I mean, he was. He must have escaped.”

“Everyone, please remain calm!” McGonagall shouted. But it was no use. Half the students were already fleeing towards their common rooms. Most of the rest were frozen in fear. Over at the Gryffindor table, Lestrade seemed to be organizing his Quidditch team into a search party.

“There’s seven of us and one of him,” John heard him say. “Let’s show that little psycho what happens when you mess with one of us!”

John had only one thought: _Find Sherlock._ He found him halfway between the Ravenclaw and Hufflepuff tables.

“You knew something was wrong,” said John. “You knew he’d escape. How?”

“He didn’t escape,” said Sherlock. “He was never caught. Notice who else is missing?”

John looked around the Great Hall, but there was no point in trying to take a head count with everyone running around like this. He tried to think back to before McGonagall’s announcement.

“Moran,” he groaned. “I knew we should have tied him up!”

Most people would have tried to make him feel better by pretending he wasn’t to blame. Sherlock wasn’t most people.

“Yes, you should have,” he said. “The idiot must have thought Moriarty would forgive him for blabbing if he warned him about you.”

“So the kid that Ron and Harry arrested—that was Moran using a Polyjuice Potion.”

“And probably under the Imperious Curse. I can’t imagine he voluntarily sacrificed himself for Moriarty.”

The fact that John didn’t even question the plausibility of a twelve-year-old using an Unforgivable Curse said a lot about his life, none of it good.

“So where do we look first?” he asked.

“Nowhere,” Sherlock sighed.

“What do you mean, nowhere?”

“ _Think,_ John. When Potter went to check on Moriarty and found Moran instead, what was the first thing he did? Check the Marauder’s Map, of course. If he didn’t see Moriarty on there, then he’s not on school grounds anymore. It’s too late.”

As usual, Sherlock was absolutely, infuriatingly correct. The Aurors and teachers searched all night, but to no avail. Moriarty had performed one final trick: a vanishing act.


	15. Epilogue

**Summary for the Chapter:**

> The case is over, but the story continues.

The next morning, John ate breakfast surrounded by dozens of black-and-white, miniature Jim Moriartys. _The Daily Prophet,_ which hadn’t printed a word on the case while it was ongoing, now felt it merited the front page.

“Citizens are warned that Moriarty is cunning and, despite his youth, extremely dangerous,” Mike read aloud. “Any sightings should be reported to the Ministry immediately. DO NOT approach him yourself.”

John snorted. “As if Moriarty’s stupid enough to go strutting down Diagon Alley with half the Ministry after him.”

Though the article described Moriarty’s crimes in graphic detail, it said very little about the details of the investigation. There was no mention at all of John, Sherlock, or Irene Adler. John was torn between indignation and relief. Obviously, they deserved some credit, but he didn’t want reporters hounding him with questions. He was already getting enough of that from his classmates. 

Everyone wanted to hear his side of the story. He was bombarded with questions in the Great Hall, in the common room, even in the loo. It was exhausting. He was grateful to his teachers for ensuring that he was at least left alone during classes.

“I’m beginning to think being a hero is overrated,” he confessed to Professor Longbottom.

Longbottom chuckled. “Harry could have told you that.”

But if he thought for one moment that it wasn’t all worth it, those doubts vanished when he entered the Hufflepuff common room one morning and found Molly sitting by the fire, looking ridiculously healthy for someone who’d spent the last week in a coma.

“I’m so sorry about Jim,” she said, flinging her arms around his waist. “I can’t believe it was him all along. I feel so stupid.”

John hugged her back. “He fooled everyone. Don’t beat yourself up over that.”

Molly looked up at him, her brown eyes even wider than usual.

“They say it was you and Sherlock who sorted it all out.”

“Well, it was mostly Sherlock. And we had some help from the Aurors, and Irene Adler, if you can believe it. But yeah, I did a bit.”

“I knew you must be clever to be friends with Sherlock.”

John laughed. “I don’t know about that. I think Sherlock just likes having someone to bounce ideas off of. Anyone could take my place.”

“That’s not true!” Molly shook her head vigorously. “Sherlock never bounces ideas off of anyone else. Not even when I—when they offer.” She look nearly as sad as she had when talking about Moriarty.

The next time John saw Sherlock, he didn’t waste any time on pleasantries.

“You need to be nicer to Molly.”

Sherlock looked up from his book, startled. “What?”

“You heard me. She’s a lovely girl, and she deserves better. Besides, you need more friends than just me.”

“Why?” It was an honest question.

“Because friends protect people, and you need more protection than most, and I can’t be with you every second of every day.”

Sherlock sighed. “Oh, very well. I suppose it wouldn’t disrupt my work too much to occasionally… _chat_ with Molly.” He said the word _chat_ as though it were something distasteful.

John smiled. Maybe he would be a good influence on Sherlock, after all.

* * *

A few days later, John asked: “Where do you think he is now?”

Sherlock didn’t need to ask who he was talking about.

“Lying low in some Muggle village, I expect,” he said. “He can’t use magic, after all.”

For the first time, John felt a shred of hope. He’d forgotten about the spells the Ministry of Magic used to deter underage wizards from using magic outside of school.

“If he can’t use magic, then he couldn’t have gotten far,” he said.

“Unless he hid in the back of a train or a lorry.”

And just like that, the shred was gone. “Oh. Right.”

“He’ll be in a city by now,” Sherlock continued matter-of-factly. “London or Manchester, or maybe even Paris. In an urban setting, he’ll be like the proverbial needle in a haystack.”

John studied his friend’s countenance. “You’re awfully calm about this.”

Sherlock shrugged. “Fretting won’t make Moriarty any easier to find. Besides, it’s not our fault the Aurors let him slip through their fingers. We did our part. We solved the case.”

Despite his words, he looked morose. John wondered briefly if he was putting on a brave face, but then he realized the truth: Sherlock wasn’t depressed that Moriarty escaped. He was depressed that the case was over.

Moriarty was a lunatic, but he’d been right about one thing. Without the mystery of the serial poisoner to keep him occupied, Sherlock would be bored out of his miraculous mind. John thought back to the day they’d met, to the stoic, solitary boy getting beaten up by a gang of Slytherins. Was that all the future had in store for Sherlock Holmes?

“Oy! Holmes!”

Greg Lestrade burst into the Great Hall, red-faced and out of breath.

“You’d better get down to the Quidditch pitch,” he gasped. “We’ve been robbed.”

Sherlock surveyed him coolly. “Stolen broomsticks? I hardly think—”

“Not brooms,” said Lestrade. “The entire bloody _pitch_ is gone.”

Sherlock closed his book. “What do you mean? How can a pitch be gone?”

“It’s just gone. Hoops, stands, everything! There’s nothing left but a giant patch of grass!”

John gaped. “Who at Hogwarts has that kind of power? And why would they—”

He turned to address Sherlock, but found himself staring at an empty chair. Sherlock was already out the door.

“Come on, John!” he called. “The game is afoot!”

And John ran after him, grinning from ear to ear.

**Notes for the Chapter:**

> That’s all, folks. Thank you so much for sticking with me all this time. It’s been one heck of a journey.
> 
> I’m already hard at work on my next multi-chapter story. It’s a _Merlin_ AU fic, but don’t worry—I’m nowhere near done with _Sherlock._
> 
> By the way, I’ve also started a [vlog.](http://www.youtube.com/user/SomeNerdyVlogger/videos?view=0&flow=grid) You should check it out. ;-)


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